[Federal Register Volume 88, Number 71 (Thursday, April 13, 2023)]
[Proposed Rules]
[Pages 22790-22857]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-06676]



[[Page 22789]]

Vol. 88

Thursday,

No. 71

April 13, 2023

Part IV





Environmental Protection Agency





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40 CFR Part 63





National Emission Standards for Hazardous Air Pollutants: Ethylene 
Oxide Emissions Standards for Sterilization Facilities Residual Risk 
and Technology Review; Proposed Rule

  Federal Register / Vol. 88, No. 71 / Thursday, April 13, 2023 / 
Proposed Rules  

[[Page 22790]]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 63

[EPA-HQ-OAR-2019-0178; FRL-7055-03-OAR]
RIN 2060-AU37


National Emission Standards for Hazardous Air Pollutants: 
Ethylene Oxide Emissions Standards for Sterilization Facilities 
Residual Risk and Technology Review

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The U.S. Environmental Protection Agency (EPA) is proposing 
amendments to the National Emission Standards for Hazardous Air 
Pollutants (NESHAP) for the Commercial Sterilization Facilities source 
category. The EPA is proposing decisions concerning the risk and 
technology review (RTR), including proposing amendments pursuant to the 
technology review for certain point source emissions and proposing 
amendments pursuant to the risk review to specifically address ethylene 
oxide (EtO) emissions from point source and room air emissions from all 
commercial sterilization facilities. The EPA is also proposing 
amendments to correct and clarify regulatory provisions related to 
emissions during periods of startup, shutdown, and malfunction (SSM), 
including removing general exemptions for periods of SSM and adding 
work practice standards for periods of SSM where appropriate. Lastly, 
the EPA is proposing to revise monitoring and performance testing 
requirements and to add provisions for electronic reporting of 
performance test results and reports, performance evaluation reports, 
and compliance reports. We estimate that, if finalized, these proposed 
amendments would reduce EtO emissions from this source category by 19 
tons per year (tpy) and reduce risks to public health to acceptable 
levels.

DATES: Comments must be received on or before June 12, 2023. 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 May 15, 2023.
    Public hearing: The EPA will hold virtual public hearings on May 2 
and May 3, 2023. See SUPPLEMENTARY INFORMATION for information on the 
public hearings.

ADDRESSES: You may send comments, identified by Docket ID No. EPA-HQ-
OAR-2019-0178, by any of the following methods:
     Federal eRulemaking Portal: https://www.regulations.gov/ 
(our preferred method). Follow the online instructions for submitting 
comments.
     Email: [email protected]. Include Docket ID No. EPA-
HQ-OAR-2019-0178 in the subject line of the message.
     Fax: (202) 566-9744. Attention Docket ID No. EPA-HQ-OAR-
2019-0178.
     Mail: U.S. Environmental Protection Agency, EPA Docket 
Center, Docket ID No. EPA-HQ-OAR-2019-0178, Mail Code 28221T, 1200 
Pennsylvania Avenue NW, Washington, DC 20460.
     Hand/Courier Delivery: EPA Docket Center, WJC West 
Building, Room 3334, 1301 Constitution Avenue NW, Washington, DC 20004. 
The Docket Center's hours of operation are 8:30 a.m.-4:30 p.m., Monday-
Friday (except Federal holidays).
    Instructions: All submissions received must include the Docket ID 
No. for this rulemaking. Comments received may be posted without change 
to https://www.regulations.gov/, including any personal information 
provided. For detailed instructions on sending comments and additional 
information on the rulemaking process, see the SUPPLEMENTARY 
INFORMATION section of this document.

FOR FURTHER INFORMATION CONTACT: For questions about this proposed 
action, contact Jonathan Witt, Sector Policies and Programs Division 
(E143-05), Office of Air Quality Planning and Standards, U.S. 
Environmental Protection Agency, Research Triangle Park, North Carolina 
27711; telephone number: (919) 541-5645; and email address: 
[email protected]. For specific information regarding the risk modeling 
methodology, contact Matt Woody, Health and Environmental Impacts 
Division (C539-02), Office of Air Quality Planning and Standards, U.S. 
Environmental Protection Agency, Research Triangle Park, North Carolina 
27711; telephone number: (919) 541-1535; and email address: 
[email protected].

SUPPLEMENTARY INFORMATION: 
    Participation in virtual public hearing. The public hearings will 
be held via virtual platform on May 2 and May 3, 2023, and will convene 
at 11:00 a.m. Eastern Time (ET) and conclude at 7:00 p.m. ET each day. 
On each hearing day, the EPA may close a session 15 minutes after the 
last pre-registered speaker has testified if there are no additional 
speakers. The EPA will announce further details at https://www.epa.gov/stationary-sources-air-pollution/ethylene-oxide-emissions-standards-sterilization-facilities. If the EPA receives a high volume of 
registrations for the public hearing, we may continue the public 
hearing on May 4, 2023.
    The EPA will begin pre-registering speakers for the hearing no 
later than 1 business day following the publication of this document in 
the Federal Register. To register to speak at the virtual hearing, 
please use the online registration form available at https://www.epa.gov/stationary-sources-air-pollution/ethylene-oxide-emissions-standards-sterilization-facilities or contact the public hearing team 
at (888) 372-8699 or by email at [email protected]. The last 
day to pre-register to speak at the hearing will be April 24, 2023. 
Prior to the hearing, the EPA will post a general agenda that will list 
pre-registered speakers in approximate order at: https://www.epa.gov/stationary-sources-air-pollution/ethylene-oxide-emissions-standards-sterilization-facilities.
    The EPA will make every effort to follow the schedule as closely as 
possible on the day of the hearing. However, please plan for the 
hearings to run either ahead of schedule or behind schedule.
    Each commenter will have 4 minutes to provide oral testimony. The 
EPA encourages commenters to submit a copy of their oral testimony as 
written comments to the rulemaking docket.
    The EPA may ask clarifying questions during the oral presentations 
but will not respond to the presentations at that time. Written 
statements and supporting information submitted during the comment 
period will be considered with the same weight as oral testimony and 
supporting information presented at the public hearing.
    Please note that any updates made to any aspect of the hearing will 
be posted online at https://www.epa.gov/stationary-sources-air-pollution/ethylene-oxide-emissions-standards-sterilization-facilities. 
While the EPA expects the hearing to go forward as set forth above, 
please monitor our website or contact the public hearing team at (888) 
372-8699 or by email at [email protected] to determine if there 
are any updates. The EPA does not intend to publish a document in the 
Federal Register announcing updates.
    If you require the services of a translator or special 
accommodation such as audio description, please pre-

[[Page 22791]]

register for the hearing with the public hearing team and describe your 
needs by April 18, 2023. The EPA may not be able to arrange 
accommodations without advanced notice.
    Docket. The EPA has established a docket for this rulemaking under 
Docket ID No. EPA-HQ-OAR-2019-0178. All documents in the docket are 
listed in https://www.regulations.gov/. Although listed, some 
information is not publicly available, e.g., Confidential Business 
Information (CBI) or other information whose disclosure is restricted 
by statute. Certain other material, such as copyrighted material, is 
not placed on the internet and will be publicly available only in hard 
copy. With the exception of such material, publicly available docket 
materials are available electronically in Regulations.gov. All publicly 
available docket materials are available in hard copy at the EPA Docket 
Center, EPA WJC West Building, Room 3334, 1301 Constitution Ave. 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-
2019-0178. The EPA's policy is that all comments received will be 
included in the public docket without change and may be made available 
online at https://www.regulations.gov/, including any personal 
information provided, unless the comment includes information claimed 
to be CBI or other information whose disclosure is restricted by 
statute. Do not submit electronically to https://www.regulations.gov/ 
any information that you consider to be CBI or other information whose 
disclosure is restricted by statute. This type of information should be 
submitted as discussed below.
    The EPA may publish any comment received to its public docket. 
Multimedia submissions (audio, video, etc.) must be accompanied by a 
written comment. The written comment is considered the official comment 
and should include discussion of all points you wish to make. The EPA 
will generally not consider comments or comment contents located 
outside of the primary submission (i.e., on the web, cloud, or other 
file sharing system). For additional submission methods, the full EPA 
public comment policy, information about CBI or multimedia submissions, 
and general guidance on making effective comments, please visit https://www.epa.gov/dockets/commenting-epa-dockets.
    The https://www.regulations.gov/ website allows you to submit your 
comment anonymously, which means the EPA will not know your identity or 
contact information unless you provide it in the body of your comment. 
If you send an email comment directly to the EPA without going through 
https://www.regulations.gov/, your email address will be automatically 
captured and included as part of the comment that is placed in the 
public docket and made available on the internet. If you submit an 
electronic comment, the EPA recommends that you include your name and 
other contact information in the body of your comment and with any 
digital storage media you submit. If the EPA cannot read your comment 
due to technical difficulties and cannot contact you for clarification, 
the EPA may not be able to consider your comment. Electronic files 
should not include special characters or any form of encryption and be 
free of any defects or viruses. For additional information about the 
EPA's public docket, visit the EPA Docket Center homepage at https://www.epa.gov/dockets.
    The EPA is soliciting comment on numerous aspects of this action. 
The EPA has indexed each comment solicitation with an alpha-numeric 
identifier (e.g., ``C-1,'' ``C-2,'' ``C-3'') to provide a consistent 
framework for effective and efficient provision of comments. 
Accordingly, the EPA asks that commenters include the corresponding 
identifier when providing comments relevant to that comment 
solicitation. The EPA asks that commenters include the identifier in 
either a heading, or within the text of each comment (e.g., ``In 
response to solicitation of comment C-1, . . .'') to make clear which 
comment solicitation is being addressed. The EPA emphasizes that the 
Agency is not limiting comment to these identified areas and encourages 
provision of any other comments relevant to this action.
    Submitting CBI. Do not submit information containing CBI to the EPA 
through https://www.regulations.gov/. 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 and note the docket ID. 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.
    Our preferred method to receive CBI is for it to be transmitted 
electronically using email attachments, File Transfer Protocol (FTP), 
or other online file sharing services (e.g., Dropbox, OneDrive, Google 
Drive). Electronic submissions must be transmitted directly to the 
OAQPS CBI Office at the email address [email protected] and, as 
described above, should include clear CBI markings and note the docket 
ID. If assistance is needed with submitting large electronic files that 
exceed the file size limit for email attachments, and if you do not 
have your own file sharing service, please email [email protected] to 
request a file transfer link. If sending CBI information through the 
postal service, please send it 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-2019-0178. The mailed CBI material should be double wrapped 
and clearly marked. Any CBI markings should not show through the outer 
envelope.
    Preamble acronyms and abbreviations. Throughout this document the 
use of ``we,'' ``us,'' or ``our'' is intended to refer to the EPA. 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:

ADAF age-dependent adjustment factor
AEGL acute exposure guideline level
AERMOD air dispersion model used by the HEM model
AIHA American Industrial Hygiene Association
APCD air pollution control device
ARV aeration room vent
ASME American Society of Mechanical Engineers
ATSDR Agency for Toxic Substances and Disease Registry
CAA Clean Air Act
CalEPA California EPA
CBI Confidential Business Information

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CEMS continuous emissions monitoring system
CEV chamber exhaust vent
CFR Code of Federal Regulations
cfs cubic feet per second
dscfm dry standard cubic feet per minute
EJ environmental justice
EPA Environmental Protection Agency
ERPG emergency response planning guideline
ERT Electronic Reporting Tool
EtO ethylene oxide
FIFRA Federal Insecticide, Fungicide, and Rodenticide Act
FR Federal Register
FTIR Fourier Transform Infrared Spectroscopy
GACT generally available control technology
GC gas chromatography
HAP hazardous air pollutant(s)
HCl hydrochloric acid
HEM Human Exposure Model
HF hydrogen fluoride
HQ hazard quotient
ICR Information Collection Request
IRIS Integrated Risk Information System
ISO International Organization for Standardization
km kilometer
lb/hr pounds per hour
LEL lower explosive limit
MACT maximum achievable control technology
MIR maximum individual risk
mg/L milligrams per liter
NAICS North American Industry Classification System
NDO natural draft opening
NEI National Emissions Inventory
NESHAP national emission standards for hazardous air pollutants
NIST National Institute of Standards and Technology
NTTAA National Technology Transfer and Advancement Act
OAQPS Office of Air Quality Planning and Standards
OMB Office of Management and Budget
PB-HAP hazardous air pollutants known to be persistent
and bio-accumulative in the environment
PID Proposed Interim Decision
ppbv parts per billion by volume
ppm parts per million
ppmv parts per million by volume
PoAHSM post-aeration handling of sterilized material
POM polycyclic organic matter
PpO propylene oxide
PRA Paperwork Reduction Act
PrAHSM pre-aeration handling of sterilized material
PS Performance Specification
PTE permanent total enclosure
RAC room air change
RBLC RACT/BACT/LAER Clearinghouse
REL reference exposure level
RDL Representative detection level
RFA Regulatory Flexibility Act
RfC reference concentration
RTR risk and technology review
SAB Science Advisory Board
SBAR Small Business Advocacy Review
SCV sterilization chamber vent
SSM startup, shutdown, and malfunction
TOSHI target organ-specific hazard index
tpy tons per year
TRIM.FaTE Total Risk Integrated Methodology, Environmental Fate, 
Transport, and Ecological Exposure
UF uncertainty factor
UPL upper prediction limit
[micro]g/m3 microgram per cubic meter
URE unit risk estimate
VCS voluntary consensus standards
WebFIRE Web Factor and Information Retrieval

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

I. General Information
    A. Executive Summary
    B. Does this action apply to me?
    C. 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. How do we consider risk in our decision-making?
    E. How does the EPA perform the technology review?
    F. How do we estimate risk posed by the source category?
III. Analytical Results and Proposed Decisions
    A. How are we proposing to define affected sources?
    B. What actions are we taking pursuant to CAA sections 
112(d)(2), 112(d)(3), and 112(d)(5)?
    C. What are the results of the risk assessment and analyses?
    D. What are our proposed decisions regarding risk acceptability, 
ample margin of safety, and adverse environmental effect?
    E. What environmental justice analysis did we conduct?
    F. What are the results and proposed decisions based on our 
technology review, and what is the rationale for those decisions?
    G. What other actions are we proposing, and what is the 
rationale for those actions?
    H. What compliance dates are we proposing, and what is the 
rationale for the proposed compliance dates?
IV. 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?
V. Request for Comments
VI. Incorporation by Reference
VII. Statutory and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Review and 
Executive Order 13563: Improving Regulation and Regulatory Review
    B. Paperwork Reduction Act (PRA)
    C. Regulatory Flexibility Act (RFA)
    D. Unfunded Mandates Reform Act (UMRA)
    E. Executive Order 13132: Federalism
    F. Executive Order 13175: Consultation and Coordination With 
Indian Tribal Governments
    G. Executive Order 13045: Protection of Children From 
Environmental Health Risks and Safety Risks
    H. Executive Order 13211: Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use
    I. National Technology Transfer and Advancement Act (NTTAA) and 
1 CFR Part 51
    J. Executive Order 12898: Federal Actions To Address 
Environmental Justice in Minority Populations and Low-Income 
Populations

I. General Information

A. Executive Summary

1. Purpose of the Regulatory Action
    The EPA is proposing to revise the NESHAP for Commercial 
Sterilization Facilities by both amending existing standards and 
establishing additional standards for this source category, exercising 
authority under multiple provisions of section 112 of the Clean Air Act 
(CAA). First, the EPA is proposing emission standards under CAA 
sections 112(d)(2)-(3) or (d)(5) for a number of currently unregulated 
emission sources of EtO. Second, the EPA is proposing risk-based 
standards under CAA section 112(f)(2) in order to protect public health 
with an ample margin of safety. Third, the EPA is proposing emission 
standards under CAA section 112(d)(6) based on the Agency's review of 
developments in practices, processes, and control technologies for this 
source category.
    This proposed rulemaking reflects the EtO toxicological assessment 
that the EPA's Integrated Risk Information System (IRIS) Program 
completed in December 2016,\1\ which indicated that EtO is a far more 
potent carcinogen than EPA had understood at the time of the previous 
RTR for this source category. There are 86 commercial sterilization 
facilities in this source category, many of which are located near 
residences, schools, and other public facilities. Many of these 
facilities are also located in communities with environmental justice 
(EJ) concerns. The EPA has determined that approximately 23 of these 
facilities pose elevated lifetime cancer risks to the surrounding 
communities, some of which are exceptionally high. Throughout this 
rulemaking process, we have engaged in

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outreach activities to these communities, along with their state and 
local governments.
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    \1\ Evaluation of the Inhalation Carcinogenicity of Ethylene 
Oxide, December 2016, EPA/635/R-16/350Fc.
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    This important action, if finalized, will reduce EtO emissions and 
lifetime cancer risks in multiple communities across the country, 
including communities with EJ concerns, and it proposes to update our 
standards considering proven and cost-effective control technologies 
that are already in use at some facilities in this source category. 
Recognizing that EPA now has additional information about the health 
risks of EtO that was not available at the time of the last RTR, and in 
order to ensure that EPA's standards for this source category 
adequately protect public health, we have also conducted a second 
residual risk review under CAA section 112(f)(2), as discussed in 
section I.A.3 of this preamble.
    In deciding whether to conduct a second residual risk review, we 
considered the advantages of EtO reductions and the distribution of 
those reductions consistent with the clear goal of CAA section 
112(f)(2) to protect the most exposed and susceptible populations, 
which in this case include communities with EJ concerns. While 
commercial medical device sterilizers provide a critical benefit for 
the health of all, sparing Americans who live near commercial 
sterilization facilities the disproportionate risk of being 
significantly harmed by toxic pollution is also essential.
    Commercial sterilization facilities play a vital role in 
maintaining an adequate supply of medical devices. According to the 
U.S. Food and Drug Administration (FDA), ``Literature shows that about 
fifty percent of all sterile medical devices in the U.S. are sterilized 
with ethylene oxide.'' FDA also notes that, ``For many medical devices, 
sterilization with ethylene oxide may be the only method that 
effectively sterilizes and does not damage the device during the 
sterilization process.'' \2\ In developing this proposed rule, EPA has 
given careful consideration to the important function these facilities 
serve, drawing from extensive engagement with industry stakeholders as 
well as Federal agencies with expertise in and responsibility for the 
medical supply chain.
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    \2\ https://www.fda.gov/medical-devices/general-hospital-devices-and-supplies/sterilization-medical-devices.
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    In order to ensure EPA's actions with respect to this source 
category are based on the most accurate and complete information 
possible, we have had many interactions with the EtO commercial 
sterilization industry in recent years, including meetings, requests 
for information, and outreach specific to this proposed rulemaking. 
This has enabled EPA to work from the best possible information when 
conducting the analyses to support this proposed rulemaking, including 
the current configuration of facilities and the performance of control 
technologies that are currently used.
    We have engaged with the U.S. Department of Health and Human 
Services, particularly FDA, regarding the potential impacts of this 
proposal on commercial sterilization facilities. These discussions have 
focused on identifying and addressing any potential concerns regarding 
the potential impact on the availability of certain medical devices 
that are sterilized with EtO where alternative sterilization methods 
are not readily available, including those that are (1) Experiencing or 
at risk of experiencing a shortage, (2) in high demand as a result of 
the COVID-19 pandemic, (3) used in pediatric services, and/or (4) 
sterilized exclusively at a particular facility.
    In this rulemaking, we are proposing a set of standards that we 
believe are achievable and reflect techniques and control technologies 
that are currently used within the industry. We are also proposing to 
provide sufficient time to enable these facilities to continue 
sterilizing essential products while installing and testing new control 
systems and associated equipment that will afford ample protection for 
nearby communities. In terms of potential impacts to the medical device 
supply chain, we project that the largest impacts are limited to a 
handful of companies, and those that are also involved in sterilizing 
the types of medical devices previously mentioned are already in the 
planning stage for additional controls.
2. Summary of the Major Provisions of the Regulatory Action in Question
    The EPA is proposing numeric emission limits, operating limits, and 
management practices under CAA sections 112(d)(2)-(3), (d)(5), and 
(d)(6) for EtO emissions from certain emission sources and is also 
proposing standards under CAA section 112(f)(2) for certain emission 
sources in order to ensure that the standards provide an ample margin 
of safety to protect public health.
    For the following emission sources that are currently 
unregulated,\3\ the EPA is proposing to set standards under CAA 
sections 112(d)(2)-(3) or (d)(5): sterilization chamber vent (SCV), 
aeration room vent (ARV), and chamber exhaust vent (CEV) at facilities 
where EtO use is less than 1 tpy, ARV and CEV at facilities where EtO 
use is at least 1 tpy but less than 10 tpy, CEV at facilities where EtO 
use is at least 10 tpy,\4\ and room air emissions.\5\
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    \3\ In 1992, pursuant to CAA section 112(c)(1), the EPA 
published a list of major and area sources for regulation under CAA 
section 112, including major and area sources of commercial 
sterilizers. 57 FR 31576, 31586 (July 16, 1992). Area sources of 
commercial sterilizers were listed for regulation under CAA section 
112(c)(3) based on the EPA's finding that it presents a threat of 
adverse effects to human health or the environment (by such sources 
individually or in the aggregate) warranting regulation under that 
section. Id. at 31586.
    \4\ The standards for CEVs were originally promulgated on 
December 6, 1994. Following promulgation of the rule, the EPA 
suspended certain compliance deadlines and ultimately removed the 
standards for CEVs due to safety concerns. In the late 1990s, there 
were multiple explosions at EtO commercial sterilization facilities 
using oxidizers to control emissions from the CEV. For CEVs, it was 
determined that the primary contributing issue leading to the 
explosions was that EtO concentrations were above a safe level 
(i.e., above the lower explosive limit (LEL)) within the CEV gas 
streams. The EPA could not conclude at the time that the CEVs could 
be safely controlled, so the standards for CEVs were removed on 
November 2, 2001 (66 FR 55583) and have not been re-instated.
    \5\ As discussed in section II.F.1, room air emissions include 
emissions resulting from indoor EtO storage, EtO dispensing, vacuum 
pump operation, pre-aeration handling of sterilized material, and 
post-aeration handling of sterilized material.
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    Next, based on the EPA's assessment of the residual risk after 
considering the emission reductions from the current standards in 
subpart O, as well as the proposed standards for the currently 
unregulated sources, the EPA is proposing more stringent standards to 
address risk for the following types of sources under CAA section 
112(f)(2):
     SCVs at facilities where EtO use is at least 40 tpy.
     SCVs at facilities where EtO use is at least 10 tpy but 
less than 40 tpy.
     SCVs at facilities where EtO use is at least 1 tpy but 
less than 10 tpy.
     Group 2 room air emissions \6\ at area source facilities 
where EtO use is at least 20 tpy.
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    \6\ As discussed in section III.B.8, Group 2 room air emissions 
cover post-aeration handling of sterilized material.
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    Finally, under CAA section 112(d)(6), the EPA is proposing to 
revise standards for the following sources that are regulated in the 
current 40 CFR part 63, subpart O:
     SCVs at facilities where EtO use is at least 10 tpy.
     SCVs at facilities where EtO use is at least 1 tpy but 
less than 10 tpy.
     ARVs at facilities where EtO use is at least 10 tpy.
    To demonstrate compliance with the emission limits, the EPA is 
proposing

[[Page 22794]]

capture requirements. The EPA is also proposing that facilities either 
monitor with an EtO continuous emissions monitoring system (CEMS) or 
conduct initial and annual performance tests with continuous parameter 
monitoring.
3. EPA Authority
    The EPA notes that it completed a residual risk and technology 
review under CAA sections 112(f)(2) and 112(d)(6), respectively, for 
this source category in 2006 (71 FR 17712). While CAA section 112(f)(2) 
requires only a one-time risk review, which is to be conducted within 
eight years of the date the initial standards are promulgated, it does 
not limit the EPA's discretion or authority to conduct another risk 
review should the EPA consider that such review is warranted. As 
discussed in more detail in section III.C of this preamble, as our 
understanding of the health effects of EtO developed, the EPA conducted 
a second residual risk review under CAA section 112(f)(2) for 
commercial sterilization facilities using ethylene oxide in order to 
ensure that the standards provide an ample margin of safety to protect 
public health.
    As discussed in further detail in section III.C, this second 
residual risk review also encompasses certain area sources for which 
EPA did not evaluate residual risk in its 2006 rulemaking. Although CAA 
section 112(f)(5) states that a risk review is not required for 
categories of area sources subject to generally available control 
technology (GACT) standards, it does not prohibit such review. In 2006, 
the EPA undertook a CAA section 112(f)(2) analysis only for area source 
emissions standards that were issued as maximum achievable control 
technology (MACT) standards and exercised its discretion under CAA 
section 112(f)(5) to not do a CAA section 112(f)(2) analysis for those 
emission points for which GACT standards were established (67 FR 
17715). However, as the EPA made clear in that prior risk assessment, 
``[w]e have the authority to revisit (and revise, if necessary) any 
rulemaking if . . . significant improvements to science [suggest that] 
the public is exposed to significant increases in risk as compared to 
the [2006 risk assessment].'' Id. In light of the updated unit risk 
estimate (URE) for EtO, which is approximately 60 times greater than 
the value the EPA used in its previous risk assessment, the EPA is now 
exercising its discretionary authority to conduct another CAA section 
112(f)(2) analysis and to include in this analysis area sources of 
commercial sterilizers using EtO for which the EPA has promulgated, or 
is now proposing, GACT standards.
    Section 112(d)(6) of the CAA also requires the EPA to review and 
revise, as necessary, standards promulgated under CAA section 112 at 
least every 8 years, taking into account developments in practices, 
processes, and control technologies. The EPA last completed this 
required technology review for the Ethylene Oxide Commercial 
Sterilization NESHAP (40 CFR 63, subpart O) in 2006. Accordingly, in 
this proposed action the EPA is also conducting a CAA section 112(d)(6) 
review for this source category.
4. Costs and Benefits
    Table 1 of this preamble summarizes the costs of this proposed 
action for 40 CFR part 63, subpart O (Ethylene Oxide Commercial 
Sterilization NESHAP).

                               Table 1--Summary of Costs of the Proposed Standards
                                                 [2021 Dollars]
----------------------------------------------------------------------------------------------------------------
                                                                                   Total annual
                                                   Total capital       Total       operation and   Total annual
                   Requirement                      investment      annualized      maintenance        cost
                                                                   capital costs       costs
----------------------------------------------------------------------------------------------------------------
Permanent total enclosure.......................     $65,798,622      $6,577,542        $430,729      $7,008,271
Additional gas/solid reactors...................     133,890,631      13,384,341      18,991,555      32,375,896
Cycle revalidations.............................               0               0       2,490,000       2,490,000
Monitoring and testing..........................      19,925,046       2,936,022       8,232,973      11,168,996
Recordkeeping and reporting.....................               0               0       8,618,124  \1\ 15,166,922
                                                 ---------------------------------------------------------------
    Total.......................................     219,614,299      22,897,905      38,763,381      68,210,084
----------------------------------------------------------------------------------------------------------------
\1\ This includes $6,548,798 of one-time annual costs for reading the rule, developing record systems, and
  initial title V permitting.

    Consistent with the compliance deadlines proposed in this rule, EPA 
has assumed for purposes of this analysis that all capital costs and 
one-time annual costs would be incurred within 18 months of the 
publication of a final rule. The capital costs for permanent total 
enclosure (PTE) and additional gas/solid reactors were annualized to 20 
years. We estimate that, if finalized, these proposed amendments would 
reduce EtO emissions from this source category by 19 tpy. Table 2 of 
this preamble summarizes the cancer risk reductions that would result 
from the proposed amendments.

               Table 2--Summary of Cancer Risk Reductions
------------------------------------------------------------------------
                                                        Cancer risks if
                                    Current cancer         proposed
                                         risks          amendments are
                                                           finalized
------------------------------------------------------------------------
Maximum Individual Risk (MIR)     6,000-in-1 million  100-in-1 million.
 \1\.
Number of People with Cancer      18,000............  0.
 Risks >100-in-1 million.
Number of People with Cancer      8.3 million.......  1.26 million. \2\
 Risks >=1-in-1 million.
Estimated Annual Cancer           0.9...............  0.1.
 Incidence (cases per year).
------------------------------------------------------------------------
\1\ The MIR is defined as the cancer risk associated with a lifetime of
  continuous exposure at the highest concentration of HAP where people
  are likely to live.
\2\ As discussed in section III, this value may be lower because the
  proposed Group 1 room air emission standards were not applied or
  accounted for in the risk assessment.


[[Page 22795]]

    As indicated in Table 2, EPA projects that the standards in the 
proposed rule would significantly reduce incremental lifetime cancer 
risks associated with emissions of EtO from this source category. 
Currently, EPA estimates that the maximum increase in lifetime cancer 
risk associated with any facility in this source category is 6,000-in-1 
million, and that approximately 18,000 people are exposed to EtO from 
this source category at levels that would correspond to a lifetime 
cancer risk of greater than 100-in-1-million (which is EPA's 
presumptive upper bound for acceptable health risks). Under the 
proposed rule, no individual would be exposed to EtO at levels that 
correspond to a lifetime cancer risk of greater than 100-in-1 million, 
and the number of people with a potential risk of greater than or equal 
to 1-in-1 million would be reduced by approximately 85 percent.
    See section IV of this preamble for further discussion of the costs 
and a discussion of the benefits of the proposed standards. See section 
III.G of this preamble for discussion of the proposed revisions to 
monitoring, recordkeeping, reporting, and testing requirements. See 
section III.C and III.D for discussion of the risk assessment results.

B. Does this action apply to me?

    The standards in 40 CFR part 63, subpart O, regulate emissions of 
EtO from existing and new commercial sterilization operations. Table 3 
of this preamble lists the NESHAP and some examples of regulated 
industrial categories that are the subject of this proposal. Table 3 is 
not intended to be exhaustive, but rather provides a guide for readers 
regarding the entities that this proposed action is likely to affect. 
The proposed standards, once promulgated, will be directly applicable 
to the affected sources. Federal, state, local, and tribal government 
entities would not be affected by this proposed action. As defined in 
the Initial List of Categories of Sources Under Section 112(c)(1) of 
the Clean Air Act Amendments of 1990 (see 57 FR 31576, July 16, 1992) 
and Documentation for Developing the Initial Source Category List, 
Final Report (see EPA-450/3-91-030, July 1992), the Commercial 
Sterilization Facilities source category is any facility engaged in the 
use of EtO as a sterilant and fumigant following the production of 
various products (e.g., medical equipment and supplies) and in 
miscellaneous sterilization and fumigation operations at both major and 
area sources. These commercial sterilization facilities use EtO as a 
sterilant for heat- or moisture-sensitive materials and as a fumigant 
to control microorganisms. Materials may be sterilized at the facility 
that produces or uses the product, or by contract sterilizers (i.e., 
firms under contract to sterilize products manufactured by other 
companies).

   Table 3--NESHAP and Industrial Categories Affected by This Proposed
                                 Action
------------------------------------------------------------------------
                                                              NAICS code
       Industrial category                  NESHAP               \1\
------------------------------------------------------------------------
Surgical and Medical Instrument    40 CFR part 63, subpart        339112
 Manufacturing.                     O.
Surgical Appliance and Supplies    40 CFR part 63, subpart        339113
 Manufacturing.                     O.
Pharmaceutical Preparation         40 CFR part 63, subpart        325412
 Manufacturing.                     O.
Spice and Extract Manufacturing..  40 CFR part 63, subpart        311942
                                    O.
Dried and Dehydrated Food          40 CFR part 63, subpart        311423
 Manufacturing.                     O.
Packaging and Labeling Services..  40 CFR part 63, subpart        561910
                                    O.
------------------------------------------------------------------------
\1\ North American Industry Classification System.

C. 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/ethylene-oxide-emissions-standards-sterilization-facilities. 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.
    A memorandum showing the rule edits that would be necessary to 
incorporate the changes to 40 CFR part 63, subpart O, proposed in this 
action is available in the docket (Docket ID No. EPA-HQ-OAR-2019-0178). 
Following signature by the EPA Administrator, the EPA also will post a 
copy of this document to https://www.epa.gov/stationary-sources-air-pollution/ethylene-oxide-emissions-standards-sterilization-facilities.

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 Clean Air Act (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 MACT and GACT standards set under CAA section 112 every 8 
years and revise the standards as necessary taking into account any 
``developments in practices, processes, or control technologies.'' This 
review is commonly referred to as the ``technology review.'' 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

[[Page 22796]]

other sources are ``area sources.'' For major sources, CAA section 
112(d)(2) provides that the technology-based NESHAP must reflect the 
maximum degree of emission reductions of HAP achievable (after 
considering cost, energy requirements, and non-air quality health and 
environmental impacts). These standards are commonly referred to as 
MACT standards. CAA section 112(d)(3) also establishes a minimum 
control level for MACT standards, known as the MACT ``floor.'' In 
certain instances, as provided in CAA section 112(h), the EPA may set 
work practice standards in lieu of numerical emission standards. The 
EPA must also consider control options that are more stringent than the 
floor. Standards more stringent than the floor are commonly referred to 
as beyond-the-floor standards. For area sources, CAA section 112(d)(5) 
allows the EPA to set standards based on GACT in lieu of MACT 
standards. For categories of major sources and any area source 
categories subject to MACT standards, the second stage in standard-
setting focuses on identifying and addressing any remaining (i.e., 
``residual'') risk pursuant to CAA section 112(f). Section 112(f) 
specifically states that EPA ``shall not be required'' to conduct risk 
review under this subsection for categories of area sources subject to 
GACT standards but does not limit the EPA's authority or discretion 
from conducting such review. As discussed in more detail in section 
III.C of this preamble, in light of the updated URE regarding EtO, the 
EPA is choosing to exercise that discrection.
    The second stage in standard-setting focuses on identifying and 
addressing any remaining (i.e., ``residual'') risk pursuant to CAA 
section 112(f). For source categories subject to MACT standards, 
section 112(f)(2) of the CAA requires the EPA to determine whether 
promulgation of additional standards is needed to provide an ample 
margin of safety to protect public health or to prevent an adverse 
environmental effect. Section 112(d)(5) of the CAA provides that this 
residual risk review is not required for categories of area sources 
subject to GACT standards. Section 112(f)(2)(B) of the CAA further 
expressly preserves the EPA's use of the two-step approach for 
developing standards to address any residual risk and the Agency's 
interpretation of ``ample margin of safety'' developed in the National 
Emissions Standards for Hazardous Air Pollutants: Benzene Emissions 
from Maleic Anhydride Plants, Ethylbenzene/Styrene Plants, Benzene 
Storage Vessels, Benzene Equipment Leaks, and Coke By-Product Recovery 
Plants (Benzene NESHAP) (54 FR 38044, September 14, 1989). The EPA 
notified Congress in the Residual Risk Report that the Agency intended 
to use the Benzene NESHAP approach in making CAA section 112(f) 
residual risk determinations (EPA-453/R-99-001, p. ES-11). The EPA 
subsequently adopted this approach in its residual risk determinations 
and the United States Court of Appeals for the District of Columbia 
Circuit upheld the EPA's interpretation that CAA section 112(f)(2) 
incorporates the approach established in the Benzene NESHAP. See NRDC 
v. EPA, 529 F.3d 1077, 1083 (D.C. Cir. 2008).
    The approach incorporated into the CAA and used by the EPA to 
evaluate residual risk and to develop standards under CAA section 
112(f)(2) is a two-step approach. In the first step, the EPA determines 
whether risks are acceptable. This determination ``considers all health 
information, including risk estimation uncertainty, and includes a 
presumptive limit on maximum individual lifetime [cancer] risk (MIR) 
\7\ of approximately 1-in-10 thousand.'' (54 FR 38045) If risks are 
unacceptable, the EPA must determine the emissions standards necessary 
to reduce risk to an acceptable level without considering costs. In the 
second step of the approach, the EPA considers whether the emissions 
standards provide an ample margin of safety to protect public health 
``in consideration of all health information, including the number of 
persons at risk levels higher than approximately 1-in-1 million, as 
well as other relevant factors, including costs and economic impacts, 
technological feasibility, and other factors relevant to each 
particular decision.'' Id. The EPA must promulgate emission standards 
necessary to provide an ample margin of safety to protect public health 
or determine that the standards being reviewed provide an ample margin 
of safety without any revisions. After conducting the ample margin of 
safety analysis, we consider whether a more stringent standard is 
necessary to prevent an adverse environmental effect, taking into 
consideration costs, energy, safety, and other relevant factors.
---------------------------------------------------------------------------

    \7\ Although defined as ``maximum individual risk,'' MIR refers 
only to cancer risk. MIR, one metric for assessing cancer risk, is 
the estimated risk if an individual were exposed to the maximum 
level of a pollutant for a lifetime.
---------------------------------------------------------------------------

    CAA section 112(d)(6) separately requires the EPA to review 
standards promulgated under CAA section 112 and revise them ``as 
necessary (taking into account developments in practices, processes, 
and control technologies)'' no less often than every 8 years. In 
conducting this review, which we call the ``technology review,'' the 
EPA is not required to recalculate the MACT floors that were 
established in earlier rulemakings. Natural Resources Defense Council 
(NRDC) v. EPA, 529 F.3d 1077, 1084 (D.C. Cir. 2008). Association of 
Battery Recyclers, Inc. v. EPA, 716 F.3d 667 (D.C. Cir. 2013). The EPA 
may consider cost in deciding whether to revise the standards pursuant 
to CAA section 112(d)(6). The EPA is also required to address 
regulatory gaps, such as missing standards for listed air toxics known 
to be emitted from the source category, and any new MACT standards must 
be established under CAA sections 112(d)(2) and (3), or, in specific 
circumstances, CAA sections 112(d)(4) or (h). Louisiana Environmental 
Action Network (LEAN) v. EPA, 955 F.3d 1088 (D.C. Cir. 2020).

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

    On July 16, 1992, pursuant to CAA section 112(c)(1), the EPA listed 
certain major and area sources of HAP for regulation, including both 
major and area sources of commercial sterilization facilities. 57 FR 
31576, 31592. As explained in that document, area sources of commercial 
sterilization facilities were listed pursuant to CAA section 112(c)(3) 
based on a finding of a threat of adverse effects from commercial 
sterilizers using EtO. Id at 31588. In 1994, the EPA promulgated the 
Ethylene Oxide Emissions Standards for Sterilization Facilities NESHAP, 
40 CFR part 63, subpart O (referred to in this proposed rulemaking as 
the EtO Commercial Sterilization NESHAP) (59 FR 62589), which is 
codified at 40 CFR part 63, subpart O. The EtO Commercial Sterilization 
NESHAP regulates EtO emitted from commercial sterilization facilities. 
The current NESHAP regulates point sources of emissions, specifically 
SCVs and ARVs, at facilities that use at least 1 ton of EtO in 
sterilization or fumigation operations in each 12-month period. In a 
Federal Register document published on July 16, 1992 (57 FR 31576), the 
EPA listed for regulation both major and area sources of EtO commercial 
sterilization and fumigation operations pursuant to CAA section 
112(c)(1) and 112(c)(3) (based on a finding of a threat of adverse 
effects), respectively.
    EtO commercial sterilization covers the sterilizer process that 
uses EtO to sterilize or fumigate materials (e.g., medical equipment 
and supplies, spices, and other miscellaneous products and items). The 
original

[[Page 22797]]

rulemaking addressed EtO emissions originating from three emission 
points: SCV, ARV, and CEV. The SCV evacuates EtO from the sterilization 
chamber following sterilization, fumigation, and any subsequent gas 
washes before the chamber door is opened. The ARV evacuates EtO-laden 
air from the aeration room or chamber that is used to facilitate off-
gassing of the sterile product and packaging. The CEV evacuates EtO-
laden air from the sterilization chamber after the chamber door is 
opened for product unloading following the completion of sterilization 
and associated gas washes. Other sources of emissions within this 
source category are room air emissions from equipment used to charge 
EtO into sterilization chambers, as well as residual EtO desorbing from 
sterilized products within the facility, but the EtO Commercial 
Sterilization NESHAP does not include standards for these emissions.
    In the chamber EtO sterilization process, products and items to be 
sterilized are placed in a chamber and exposed to EtO gas at a 
predetermined concentration, temperature, humidity, and pressure for a 
period of time known as the dwell period. Following the dwell period, 
the EtO gas is evacuated from the chamber, and the sterilized materials 
are then aerated to remove residual EtO from the product. After the 
aeration step, sterilized materials are typically moved to a shipping/
warehouse area for storage until they are ready to be distributed to 
the customer. Sterilizer process equipment and emission control 
configurations vary across facilities. The most common sterilizer 
process equipment configuration includes a separate sterilizer chamber, 
separate aeration room, and chamber exhaust on the sterilizer chamber 
(also referred to as a back-vent). Another common configuration 
includes a combination sterilizer where the sterilization and aeration 
steps of the process occur within the same chamber, though this 
configuration may or may not have a chamber exhaust.
    Another EtO sterilization process is single-item sterilization 
where small individual items are sterilized in sealed pouches. EtO gas 
is introduced into the sealed pouch, either by injection or use of an 
EtO ampule, and the sealed pouch is then placed in a chamber where the 
sterilization step and aeration step occur.
    Multiple control technologies were available for EtO commercial 
sterilization at the time the EtO Commercial Sterilization NESHAP was 
promulgated (December 1994). Control technologies for SCVs included: 
acid-water scrubbers; thermal oxidizer/flares; catalytic oxidizers; 
condensers/reclaimers; and a combination packed bed scrubber and gas-
solid reactor (dry bed reactor) systems. Control technologies for CEVs 
included: packed bed scrubber; catalytic oxidizer; gas-solid reactor; 
and a combination packed bed scrubber and gas-solid reactor. Control 
technologies for ARVs included: acid-water scrubber, catalytic 
oxidizer, and gas-solid reactor.
    In 2006, the EPA finalized a residual risk review and a technology 
review under CAA section 112(f)(2) and CAA section 112(d)(6), 
respectively (71 FR 17712, April 7, 2006). No changes were made to the 
EtO Commercial Sterilization NESHAP in that action.
    The emission standards that currently apply to sterilization 
facilities covered by 40 CFR part 63, subpart O, are shown in Table 4:

                            Table 4--Current EtO Standards for Commercial Sterilizers
----------------------------------------------------------------------------------------------------------------
 Existing and new sources subcategory
 (in any consecutive 12-month period)   Sterilization chamber      Aeration room vent      Chamber exhaust vent
                 \1\                          vent (SCV)                 (ARV)                  (CEV) \2\
----------------------------------------------------------------------------------------------------------------
Sources using 10 tons or more of EtO.  99 percent emission      1 part per million       No control.
                                        reduction (see 40 CFR    (ppm) maximum outlet
                                        63.362(c)).              concentration or 99
                                                                 percent emission
                                                                 reduction (see 40 CFR
                                                                 63.362(d)).
Sources using 1 ton or more of EtO     99 percent emission      No control.............  No control.
 but less than 10 tons of EtO.          reduction (see 40 CFR
                                        63.362(c)).
Sources using less than 1 ton of EtO.  No control required;     No control required;     No control required;
                                        minimal recordkeeping    minimal recordkeeping    minimal recordkeeping
                                        requirements apply       requirements apply       requirements apply
                                        (see 40 CFR              (see 40 CFR              (see 40 CFR
                                        63.367(c))).             63.367(c))).             63.367(c))).
----------------------------------------------------------------------------------------------------------------
\1\ Determined on a rolling 12-month basis.
\2\ The CEV emission source was included in the original standard but was later eliminated from the 40 CFR part
  63, subpart O, regulation in 2001.

    We note that hospital sterilizers are regulated under a different 
NESHAP (40 CFR part 63, subpart WWWWW), which is not addressed in this 
rulemaking.\8\ We are aware of the potential risk posed by EtO 
emissions from this source category and will address hospital 
sterilizers in a future rulemaking.
---------------------------------------------------------------------------

    \8\ Hospitals are defined at 40 CFR 63.10448 to mean facilities 
that provide medical care and treatment for patients who are acutely 
ill or chronically ill on an inpatient basis under supervision of 
licensed physicians and under nursing care offered 24 hours per day. 
Hospitals include diagnostic and major surgery facilities but 
exclude doctor's offices, clinics, or other facilities whose primary 
purpose is to provide medical services to humans or animals on an 
outpatient basis.
---------------------------------------------------------------------------

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

    The EPA used several sources to develop the list of existing 
commercial sterilization facilities. We began with the facility list 
used during the previous RTR and supplemented that with facilities 
identified in the 2017 National Emissions Inventory (NEI), as well as 
facilities identified using the Office of Enforcement and Compliance 
Assurance's Enforcement and Compliance History Online tool (https://echo.epa.gov). We then reviewed available Federal, state, and local 
data to determine whether any of these facilities had closed or ceased 
using EtO for sterilization purposes. We also asked our EPA regional 
offices to identify any commercial sterilization facilities that we 
missed, and when we conducted the December 2019 CAA section 114 
questionnaire and September 2021 CAA section 114 Information Collection 
Request (ICR) (discussed below), we asked the parent companies to 
identify

[[Page 22798]]

any commercial sterilization facilities they owned that we did not 
identify. This review and analysis produced the final facility list of 
86 commercial sterilization facilities. A complete list of known 
commercial sterilization facilities is available in the document titled 
Residual Risk Assessment for the Commercial Sterilization Facilities 
Source Category in Support of the 2022 Risk and Technology Review 
Proposed Rule, which is available in the docket for this rulemaking.
    For this RTR, the EPA investigated developments in practices, 
processes, and control technologies through communications and direct 
discussions with EPA regional offices, state and local agencies, Small 
Business Environmental Assistance Program personnel, industry 
representatives, and trade association representatives. Details of 
these conversations are included in the memorandum titled Technical 
Support Document for Proposed Rule--Industry Profile, Review of 
Unregulated Emissions, CAA Section 112(d)(6) Technology Review, and CAA 
Section 112(f) Risk Assessment for the Ethylene Oxide Emissions 
Standards for Sterilization Facilities NESHAP (Technical Support 
Document), available in the docket for this action (Docket ID No. EPA-
HQ-OAR-2019-0178). The EPA conducted literature reviews, operating 
permit reviews, internet web searches, and site visits; published an 
Advanced Notice of Proposed Rulemaking (84 FR 67889, December 12, 
2019); reviewed public comments received; sent requests for information 
to industry under the authority of CAA section 114; and searched the 
EPA's Technology Transfer Network Clean Air Technology Center--RACT/
BACT/LAER Clearinghouse (RBLC) database.
    The RBLC provides several options for searching the permit database 
online to locate applicable control technologies. We queried the RBLC 
database for specific commercial sterilization Process Type 99.004 
(Commercial Sterilization Facilities), as well as a related source 
category, Process Type 99.008 (Hospital Sterilization Facilities). In 
querying results dating back to January 1, 2006 (the date of the 
residual risk and initial technology review), no results were returned 
when searching for Process Type 99.004 and no results were returned for 
Process Type 99.008. None of these searches returned relevant 
information on developments in practices, processes, or control 
technologies used in EtO commercial sterilization facilities. Full 
details of the RBLC database search in support of this technology 
review are included in the Technical Support Document, available in the 
docket for this action (Docket ID No. EPA-HQ-OAR-2019-0178). Prior to 
this proposed rulemaking, the EPA engaged in outreach activities to 
communities we expect to be impacted most by the rulemaking.\9\ Any 
information related to these outreach activities that we receive prior 
to the conclusion of the comment period will be considered as part of 
the final rulemaking, along with direct comments on this proposed 
rulemaking. Any updated emissions information received during the EPA's 
ongoing public outreach activities that may change the projected 
impacts for these populations will be considered as part of the final 
rulemaking, as well as direct comments received on this proposed 
rulemaking.
---------------------------------------------------------------------------

    \9\ https://www.epa.gov/newsreleases/epa-launches-community-engagement-efforts-new-ethylene-oxide-risk-information.
---------------------------------------------------------------------------

    The EPA issued two requests to gather information about process 
equipment, control technologies, and emissions from facilities in the 
source category. In December 2019, the EPA issued a CAA section 114 
request to a small number of entities that were operating 42 facilities 
at the time (now 39) to gather information, including information about 
types of process equipment, sterilization cycles, control technologies, 
EtO usage and storage, room areas, movements of sterilized products, 
and EtO concentration data. We also included requests for facility 
documents (e.g., process flow diagrams, air permits, air permit 
applications, process and instrumentation diagrams), performance test 
reports, parametric monitoring data, startup shutdown and malfunction 
plans, and EtO residual studies in products. These entities were 
selected because, collectively, they comprised a significant portion of 
the sterilization industry. All respondents completed the questionnaire 
and submitted responses to the EPA in February 2020. Additionally, in 
September 2021, the EPA issued an information collection request (ICR), 
pursuant to CAA section 114, to gather information from all facilities 
in the EtO commercial sterilization category. Additional questions in 
the September 2021 ICR included information on non-EtO sterilization 
techniques and stand-alone, non-co-located warehouses or distribution 
centers.\10\ The facilities not included in the December 2019 request 
were asked to respond to the full set of questions, and those 
facilities were only asked to provide responses to the additional 
questions. Responses to the ICR were due in November 2021.
---------------------------------------------------------------------------

    \10\ The EPA is not proposing requirements for these facilities 
as part of this action. However, the EPA plans to evaluate the data 
received and determine what requirements these facilities should be 
subject to, if any.
---------------------------------------------------------------------------

    The Agency made the data results from the two questionnaires 
available as part of a Freedom of Information Act request.\11\ The EPA 
used the collected information to assist in filling data gaps, 
establish the baseline emissions and control levels for purposes of the 
regulatory reviews, identify the most effective control measures, and 
estimate the environmental impacts associated with the regulatory 
options considered and reflected in this proposed action. The responses 
to the December 2019 and September 2021 questionnaires are listed in 
the memorandum titled Documentation of Database Containing Information 
from Responses to the December 2019 Questionnaire and the September 
2021 Section 114 for the Ethylene Oxide Commercial Sterilization NESHAP 
Review, which is available in the docket for this rulemaking. The 
information not claimed as CBI by respondents and received in time to 
be included in this proposal is available in the database titled Data 
Received from Information Collection Requests for the Commercial 
Sterilization Facilities Source Category, which is available in the 
docket for this rulemaking.
---------------------------------------------------------------------------

    \11\ Results from the December 2019 questionnaire are available 
at https://foiaonline.gov/foiaonline/action/public/submissionDetails?trackingNumber=EPA-2020-004133&type=Request, and 
results from the September 2021 ICR are available at https://foiaonline.gov/foiaonline/action/public/submissionDetails?trackingNumber=EPA-2022-003690&type=Request.
---------------------------------------------------------------------------

D. 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). 
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

[[Page 22799]]

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 the 
factors the EPA may consider in making determinations and how the EPA 
may weigh those factors for each source category. The EPA conducts a 
risk assessment that provides estimates of the MIR posed by emissions 
of HAP that are carcinogens from each source in the source category, 
the hazard index 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.\12\ The assessment also provides estimates of the distribution 
of cancer risk within the exposed populations, cancer incidence, and an 
evaluation of the potential for an adverse environmental effect. The 
scope of the EPA's risk analysis is consistent with the explanation in 
the EPA's response to comments on our policy under the Benzene NESHAP. 
The policy chosen by the Administrator permits consideration of 
multiple measures of health risk. Not only can the MIR figure be 
considered, but also incidence, the presence of non-cancer health 
effects, and the uncertainties of the risk estimates. In this way, the 
effect on the most exposed individuals can be reviewed as well as the 
impact on the general public. These factors can then be weighed in each 
individual case. This approach complies with the Vinyl Chloride mandate 
that the Administrator ascertain an acceptable level of risk to the 
public by employing his expertise to assess available data. It also 
complies with the congressional intent behind the CAA, which did not 
exclude the use of any particular measure of public health risk from 
the EPA's consideration with respect to CAA section 112 regulations, 
and thereby implicitly permits consideration of any and all measures of 
health risk which the Administrator, in his judgment, believes are 
appropriate to determining what will ``protect the public health'' (54 
FR 38057). Thus, the level of the MIR is only one factor to be weighed 
in determining acceptability of risk. The Benzene NESHAP explained that 
``an MIR of approximately one in 10 thousand should ordinarily be the 
upper end of the range of acceptability. As risks increase above this 
benchmark, they become presumptively less acceptable under CAA section 
112, and would be weighed with the other health risk measures and 
information in making an overall judgment on acceptability. Or, the 
Agency may find, in a particular case, that a risk that includes an MIR 
less than the presumptively acceptable level is unacceptable in the 
light of other health risk factors.'' Id. at 38045. In other words, 
risks that include an MIR above 100-in-1 million may be determined to 
be acceptable, and risks with an MIR below that level may be determined 
to be unacceptable, depending on all of the available health 
information. Similarly, with regard to the ample margin of safety 
analysis, the EPA stated in the Benzene NESHAP that: ``EPA believes the 
relative weight of the many factors that can be considered in selecting 
an ample margin of safety can only be determined for each specific 
source category. This occurs mainly because technological and economic 
factors (along with the health-related factors) vary from source 
category to source category.'' Id. at 38061. We also consider the 
uncertainties associated with the various risk analyses, as discussed 
earlier in this preamble, in our determinations of acceptability and 
ample margin of safety.
---------------------------------------------------------------------------

    \12\ The MIR is defined as the cancer risk associated with a 
lifetime of continuous exposure at the highest concentration of HAP 
where people are likely to live. The HQ is the ratio of the 
potential HAP exposure concentration to the noncancer dose-response 
value. The HI is the sum of HQs for HAP that affect the same target 
organ or organ system.
---------------------------------------------------------------------------

    The EPA notes that it has not considered certain health information 
to date in making residual risk determinations. At this time, we do not 
attempt to quantify the HAP risk that may be associated with emissions 
from other facilities that do not include the source category under 
review, mobile source emissions, natural source emissions, persistent 
environmental pollution, or atmospheric transformation in the vicinity 
of the sources in the category.
    The EPA understands the potential importance of considering an 
individual's total exposure to HAP in addition to considering exposure 
to HAP emissions from the source category and facility. We recognize 
that such consideration may be particularly important when assessing 
noncancer risk, where pollutant-specific exposure health reference 
levels (e.g., reference concentrations (RfCs)) are based on the 
assumption that thresholds exist for adverse health effects. For 
example, the EPA recognizes that, although exposures attributable to 
emissions from a source category or facility alone may not indicate the 
potential for increased risk of adverse noncancer health effects in a 
population, the exposures resulting from emissions from the facility in 
combination with emissions from all of the other sources (e.g., other 
facilities) to which an individual is exposed may be sufficient to 
result in an increased risk of adverse noncancer health effects. In May 
2010, the Science Advisory Board (SAB) advised the EPA ``that RTR 
assessments will be most useful to decision makers and communities if 
results are presented in the broader context of aggregate and 
cumulative risks, including background concentrations and contributions 
from other sources in the area.'' \13\
---------------------------------------------------------------------------

    \13\ Recommendations of the SAB Risk and Technology Review 
Methods Panel are provided in their report, which is available at: 
https://www.epa.gov/sites/default/files/2021-02/documents/epa-sab-10-007-unsigned.pdf.
---------------------------------------------------------------------------

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

E. How does the EPA perform the technology review?

    Our technology review primarily focuses on the identification and 
evaluation of developments in practices, processes, and control 
technologies that have occurred since the MACT and GACT 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

[[Page 22800]]

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 
and GACT standards;
     Any improvements in add-on control technology or other 
equipment (that were identified and considered during development of 
the original MACT and GACT 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 and 
GACT 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 and 
GACT 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 and GACT 
standards).
    In addition to reviewing the practices, processes, and control 
technologies that were considered at the time we originally developed 
or last reviewed the NESHAP, we review a variety of data sources in our 
investigation of potential practices, processes, or controls to 
consider. We also review the NESHAP and the available data to determine 
if there are any unregulated emissions of HAP within the source 
category and evaluate these data for use in developing new emission 
standards. See sections II.C and II.D of this preamble for information 
on the specific data sources that were reviewed as part of the 
technology review.

F. How do we estimate 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 hazard index 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 
eight sections that follow this paragraph describe how we estimated 
emissions and conducted the risk assessment. The docket for this 
rulemaking contains the following document that provides more 
information on the risk assessment inputs and models: Residual Risk 
Assessment for the Commercial Sterilization Facilities Source Category 
in Support of the 2022 Risk and Technology Review Proposed Rule. The 
methods used to assess risk (as described in the eight 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, 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?
    Commercial sterilizers using EtO were listed for regulation in 1992 
as described in section II.B of this preamble. The standards in the 
current NESHAP subpart O are based on facilities' EtO usage amount. 
Specifically, 40 CFR part 63, subpart O, contains SCV and ARV standards 
for facilities where EtO use is at least 10 tpy and a separate SCV 
standard for facilities where EtO use is at least 1 tpy but less than 
10 tpy. Currently there are 86 facilities in the source category. Based 
on actual EtO usage data, 47 facilities are sterilization sources where 
EtO use is at least 10 tpy, 20 facilities are sterilization sources 
where EtO use is at least 1 tpy but less than 10 tpy, and 19 facilities 
are sterilization sources where EtO use is less than 1 tpy. The EPA 
also identified, based on permits and responses to the December 2019 
questionnaire and September 2021 ICR, 11 research facilities, as 
defined under CAA 112(c)(7), which are not part of the source category.
    For these facilities, the emissions information that was derived 
from the 2014 NEI was, in general, found to be insufficient to set 
appropriate standards. Most notably, for most facilities, room air 
emissions were not accounted for in the NEI. In addition, 28 facilities 
had no Emissions Inventory System ID and, therefore, no emissions data 
to pull from the NEI. Therefore, the EPA generated new EtO emissions 
data as described below. The complete Commercial Sterilization facility 
list is available in Appendix 1 of the document titled Residual Risk 
Assessment for the Commercial Sterilization Facilities Source Category 
in Support of the 2022 Risk and Technology Review Proposed Rule, which 
is available in the docket for this rulemaking.
    In general, emissions were estimated using a mass balance approach, 
beginning with annual EtO use (i.e., the previous consecutive 12-month 
period of EtO use). Where available, the latest annual EtO usage for 
each facility was used. Where we lacked data, we assumed that the 
facility was using 50 percent of the maximum usage listed in state and 
local permits because this is the industry average. Then, EtO use was 
apportioned to the different emission process groups using emission 
factors. Emission sources from Commercial Sterilization Facilities 
include SCVs, ARVs, CEVs, and room air emission sources (descriptions 
of SCV, ARV, and CEV emission sources are provided in section II.B). 
The room air emission sources are:
     Indoor EtO storage: EtO drums and cylinders are often 
stored in storage areas inside the facility, and emissions may occur 
from improperly sealed/leaking drums and cylinders into the storage 
room area.
     EtO dispensing: This includes connecting pressurized lines 
from the storage drum or cylinder valve to the sterilization chamber to 
charge EtO to the process cycle. EtO is often moved from the drum to 
the sterilizer chamber using nitrogen. EtO drums or cylinders may sit 
in a separate room for dispensing, or the drum or cylinder may be 
placed near the sterilization chamber. In either scenario, emissions 
may occur from connectors and valves on the pressurized lines that 
connect the storage drum or cylinder to the chamber.
     Vacuum pump operation: These are often used to evacuate 
sterilization chambers before the chamber door is opened. The vacuum 
pump feeds into a separation tank where the recirculating

[[Page 22801]]

pump fluid is returned to the pump and the EtO and other gases 
(nitrogen and air) are vented to a control system or to the atmosphere. 
Emissions from leaks may occur from the vacuum pump during operation.
     Pre-aeration handling of sterilized material (PrAHSM): 
Following the sterilization cycle, emissions may occur from the 
sterilized materials when moving the material from the sterilization 
chamber to the aeration room or when holding the material within the 
facility areas. PrAHSM includes activities such as removing the 
sterilized materials from the sterilization chamber, transferring 
sterilized materials from the sterilization chamber to the aeration 
room, placing or holding of sterilized materials outside of process 
equipment for short periods of time, and, at some facilities, during 
aeration transfers where there are primary and secondary aeration 
chambers. Emissions may occur from off-gassing of residual EtO that is 
contained in the materials following exposure to EtO.
     Post-aeration handling of sterilized material (PoAHSM): 
Following the aeration step, emissions may continue to occur from the 
sterilized and aerated materials when moving the material and holding 
the material within the facility areas. PoAHSM includes activities such 
as removing the sterilized/aerated materials from the aeration room, 
transferring the sterilized/aerated materials from the aeration room to 
holding areas, placing or holding of the sterilized/aerated materials 
in a quarantine area while awaiting confirmation of sterility, and 
holding of sterilized/aerated materials in shipping and warehouse areas 
at the facility. Emissions may occur from continued off-gassing of 
residual EtO that remains in the materials even after the aeration 
step.
     Non-oxidizer air pollution control device (APCD) area: 
Non-oxidizer APCDs, such as acid-water scrubbers and gas-solid 
reactors, are typically housed within the sterilization building. 
Through the responses to the section 114 requests, we learned that 
elevated EtO concentrations were observed in the rooms where these 
APCDs were located. This is likely due to equipment leaks and/or 
emissions not being fully captured or routed under negative pressure.
    In the original rulemaking, we assumed there were no room air 
emissions. Using the emission source apportionment data available at 
that time, we assumed that 95 percent of the EtO usage was emitted 
through the SCV, 2 percent was emitted through the CEV, and 3 percent 
was emitted through the ARV.\14\ The EPA now understands that in 
addition to emissions from point sources such as SCVs, CEVs, and ARVs, 
room air emissions also occur at commercial sterilization facilities. 
In recent years, the industry has assumed a range of room air 
emissions, anywhere from 0.01 to 1.5 percent of total usage. However, 
there is little to no documentation for these assumptions or what 
emission sources were included. In 2019, the EPA examined ambient air 
monitoring data collected around a commercial sterilization facility in 
Willowbrook, Illinois, and derived a room air emissions factor that 
equates to approximately 0.6 percent of total EtO usage.\15\
---------------------------------------------------------------------------

    \14\ U.S. EPA. Ethylene Oxide Emissions from Commercial 
Sterilization/Fumigation Operations, Background Information for 
Proposed Standards. EPA Publication No. EPA-453/D-93-016. October 
1992.
    \15\ https://www.epa.gov/sites/default/files/2019-08/documents/appendix_1_to_the_sterigenics_willowbrook_risk_assessment.pdf, Table 
1.
---------------------------------------------------------------------------

    Under this rule review, the EPA reassessed the emission 
apportionment across the emission sources at commercial sterilization 
facilities. The EPA analyzed the responses from the December 2019 
questionnaire and September 2021 ICR to update the fraction of EtO that 
is apportioned to SCV, ARV, CEV, and room air emissions.
     The data for the ARV analyses included flow rate (or room 
volume combined with air changeover rate), EtO concentration, and 
average aeration room temperature to estimate ARV emissions.
     The data for the CEV analyses included flow rate, EtO 
concentration, and the sterilizer chamber temperature to estimate CEV 
emissions.
     The data for the room area analyses included the flow 
rate, EtO concentration, temperature information, and annual operating 
hours to estimate the EtO emission for each emission source.
    The estimated EtO emissions were compared to the annual actual EtO 
usage to develop the fraction of EtO use that goes to each emission 
source before controls. Under the recent emission source apportionment 
analysis, the EPA determined 4 percent of EtO used goes to the ARV, 1 
percent goes to the CEV, 0.1 percent goes to EtO dispensing, 0.1 
percent goes to vacuum pump operations, 0.2 percent goes to pre-
aeration handling of sterilized material, 0.2 percent goes to post-
aeration handling of sterilized material, and 0.04 percent goes to non-
oxidizer APCD operation. We estimate that another 1 percent of EtO used 
leaves the facility still in the product. The portion of EtO usage that 
is emitted from SCV is the balance of the EtO usage (i.e., 93.36 
percent). However, the value varies depending on the equipment 
configuration (traditional sterilizer chamber, combination chamber, 
etc.) and may range from 93.36 to 98.32 percent. The EPA was not able 
to quantify what percentage of EtO use is emitted from indoor EtO 
storage, which could result in a slight underestimation of the risk. 
Based on our review of the data, we do not believe that emissions from 
indoor EtO storage are significant. See memorandum Development of 
Ethylene Oxide Usage Fractions for Ethylene Oxide Commercial 
Sterilization--Proposal, which is available in the docket for this 
rulemaking.
    Finally, the performance of the control systems used to reduce 
emissions, if available, was considered. Data from the CAA section 114 
requests, as well as state and local permitting data, were also used to 
develop the other parameters needed to perform the risk modeling 
analysis, including the emissions release characteristics, such as 
stack heights, stack diameters, flow rates, temperatures, and emission 
release point locations.
    The RTR emissions dataset developed using the data and estimates 
described immediately above was refined following an extensive quality 
assurance check of source locations, emission release point parameters, 
and annual emission estimates. The EPA reviewed the locations of 
emission release points at each facility and revised each record as 
needed to ensure that all release points were located correctly. If an 
emission release point was located outside of the facility fenceline or 
on an obviously incorrect location within the fenceline (e.g., parking 
lot, lake, etc.) then the emission release point was relocated to 
either the true location of the equipment, if known, or the approximate 
center of the facility.
    The emission release point parameters for stacks in the modeling 
input files include stack height, exit gas temperature, stack diameter, 
exit gas velocity, and exit gas flow rate. If emission release point 
parameters were outside of typical quality assurance range checks or 
missing, then an investigation was done to determine whether these 
values were accurate. If this information could not be found, then 
surrogate values were assigned based on similar values observed for the 
control device and process group. In some cases, missing emission 
release point parameters were calculated using

[[Page 22802]]

other parameters within the modeling input file. For example, missing 
exit gas flow rates were calculated using the reported diameter and 
velocity.
    Additionally, the EPA compared the emission release point type 
(i.e., fugitive, stack) to the emission unit and process descriptions 
for the modeling file records. In cases where information was 
conflicting (i.e., equipment leaks being modeled as a vertical stack, 
or process vent emissions being modeled as a fugitive area), we updated 
the emission release point type to the appropriate category and 
supplemented the appropriate emission release parameters using either 
permitted values, when available, or default values.
2. 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). The HEM 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
    AERMOD, the air dispersion model used by the HEM model, is one of 
the EPA's preferred models for assessing air pollutant concentrations 
from industrial facilities. To perform the dispersion modeling and to 
develop the preliminary risk estimates, HEM draws on three data 
libraries. The first is a library of meteorological data, which is used 
for dispersion calculations. This library includes hourly surface and 
upper air observations for years ranging from 2016-2019 from over 800 
meteorological stations, selected to provide coverage of the United 
States and Puerto Rico. A second library of United States Census Bureau 
census block 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) 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 [mu]g/m\3\) by 
its 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 
IRIS. For carcinogenic pollutants without IRIS values, we look to other 
reputable sources of cancer dose-response values, often using CalEPA 
UREs, where available. In cases where new, scientifically credible 
dose-response values have been developed in a manner consistent with 
EPA guidelines and have undergone a peer review process similar to that 
used by the EPA, we may use such dose-response values in place of, or 
in addition to, other values, if appropriate. The pollutant-specific 
dose-response values used to estimate health risk are available at 
https://www.epa.gov/fera/dose-response-assessment-assessing-health-risks-associated-exposure-hazardous-air-pollutants.
    To estimate individual lifetime cancer risks associated with 
exposure to HAP emissions from each facility in the source category, we 
sum the risks for each of the carcinogenic HAP emitted by the modeled 
facility. We estimate cancer risk at every census block within 50 km of 
every facility in the source category. The MIR is the highest 
individual lifetime cancer risk estimated for any of those census 
blocks. In addition to calculating the MIR, we estimate the 
distribution of individual cancer risks for the source category by 
summing the number of individuals within 50 km of the sources whose 
estimated risk falls within a specified risk range. We also estimate 
annual cancer incidence by multiplying the estimated lifetime cancer 
risk at each census block by the number of people residing in that 
block, summing results for all of the census blocks, and then dividing 
this result by a 70-year lifetime.
    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) 
Minimal Risk Level (https://www.atsdr.cdc.gov/minimalrisklevels/index.html); (2) the CalEPA Chronic Reference Exposure Level (REL) 
(https://oehha.ca.gov/air/crnr/notice-adoption-air-toxics-hot-spots-program-guidance-manual-preparation-health-risk-0); or (3) as noted 
above, a scientifically credible dose-response value that has been 
developed in a manner consistent with the EPA guidelines and has 
undergone a peer review process similar to that used by the EPA. The 
pollutant-specific dose-response values used to estimate health risks 
are available at https://www.epa.gov/fera/dose-response-assessment-assessing-health-risks-associated-exposure-hazardous-air-pollutants.

[[Page 22803]]

c. Risk From Acute Exposure to HAP That May Cause Health Effects Other 
Than Cancer
    For each HAP for which appropriate acute inhalation dose-response 
values are available, the EPA also assesses the potential health risks 
due to acute exposure. For these assessments, the EPA makes 
conservative assumptions about emission rates, meteorology, and 
exposure location. As part of our efforts to continually improve our 
methodologies to evaluate the risks that HAP emitted from categories of 
industrial sources pose to human health and the environment, we revised 
our treatment of meteorological data to use reasonable worst-case air 
dispersion conditions in our acute risk screening assessments instead 
of worst-case air dispersion conditions. This revised treatment of 
meteorological data and the supporting rationale are described in more 
detail in Residual Risk Assessment for Commercial Sterilization 
Facilities Source Category in Support of the 2022 Technology Review 
Proposed Rule and in Appendix 5 of the report: Technical Support 
Document for Acute Risk Screening Assessment. This revised approach has 
been used in this proposed rule and in all other RTR rulemakings 
proposed on or after June 3, 2019.
    To assess the potential acute risk to the maximally exposed 
individual, we use the peak hourly emission rate for each emission 
point, reasonable worst-case air dispersion conditions (i.e., 99th 
percentile), and the point of highest off-site exposure. Specifically, 
we assume that peak emissions from the source category and reasonable 
worst-case air dispersion conditions co-occur and that a person is 
present at the point of maximum exposure.
    To characterize the potential health risks associated with 
estimated acute inhalation exposures to a HAP, we generally use 
multiple acute dose-response values, including acute RELs, acute 
exposure guideline levels (AEGLs), and emergency response planning 
guidelines (ERPG) for 1-hour exposure durations, if available, to 
calculate acute HQs. The acute HQ is calculated by dividing the 
estimated acute exposure concentration by the acute dose-response 
value. For each HAP for which acute dose-response values are available, 
the EPA calculates acute HQs.
    An acute reference exposure level (REL) is defined as ``the 
concentration level at or below which no adverse health effects are 
anticipated for a specified exposure duration.'' 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. 
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 or 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 by the American Industrial Hygiene Association 
(AIHA) for emergency planning and are intended to be health-based 
guideline concentrations for single exposures to chemicals. The ERPG-1 
is the maximum airborne concentration, established by AIHA, 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. 
Similarly, the ERPG-2 is the maximum airborne concentration, 
established by AIHA, 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.
    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, an acute emissions multiplier value of 
1.2 was used because, overall, sterilization operations tend to be 
steady-state without much variation. A further discussion of why this 
factor was chosen can be found in Appendix 1 of the document titled 
Residual Risk Assessment for the Commercial Sterilization Facilities 
Source Category in Support of the 2022 Risk and Technology Review 
Proposed Rule, available in the docket for this rulemaking.
    In our acute inhalation screening risk assessment, acute impacts 
are deemed negligible for HAP for which acute HQs are less than or 
equal to 1, and no further analysis is performed for these HAP. In 
cases where an acute HQ from the screening step is greater than 1, we 
assess the site-specific data to ensure that the acute HQ is at an off-
site location. For this source category, all acute HQs were less than 
or equal to 1, and no further analysis was performed.
3. How do we conduct the multipathway exposure and risk screening 
assessment?
    The EPA conducts a tiered screening assessment examining the 
potential for significant human health risks due to exposures via 
routes other than inhalation (i.e., ingestion). We first determine 
whether any sources in the source category emit any HAP known to be 
persistent and bioaccumulative in the environment, as identified in the 
EPA's Air Toxics Risk Assessment Library (see Volume 1, Appendix D, at 
https://www.epa.gov/fera/risk-assessment-and-modeling-air-toxics-risk-assessment-reference-library).
    For the Commercial Sterilization Facilities source category, we did 
not identify emissions of any PB-HAP. Because we did not identify any 
PB-HAP emissions, no further evaluation of multipathway risk was 
conducted for this source category.

[[Page 22804]]

4. How do we assess risks considering emissions control options?
    In addition to assessing baseline inhalation risks and screening 
for potential multipathway risks, we also estimate risks considering 
the potential emission reductions that would be achieved by the control 
options under consideration. In these cases, the expected emission 
reductions are applied to the specific HAP and emission points in the 
RTR emissions dataset to develop corresponding estimates of risk and 
incremental risk reductions.
5. How do we conduct the environmental risk screening assessment?
    The EPA conducts a screening assessment to examine the potential 
for an adverse environmental effect. 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 
hydrochloric acid (HCl) and hydrogen fluoride (HF).
    For the Commercial Sterilization Facilities source category, we did 
not identify emissions of any environmental HAP. Because we did not 
identify any environmental HAP emissions, no further evaluation of 
environmental risk was conducted for this source category.
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 2017 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 Commercial Sterilization Facilities Source Category 
in Support of the Risk and Technology Review 2022 Proposed Rule, 
available through the docket for this action, provides the methodology 
and results of the facility-wide analyses, including all facility-wide 
risks and the percentage of source category contribution to facility-
wide risks.
7. How do we consider uncertainties in risk assessment?
    Uncertainty and the potential for bias are inherent in all risk 
assessments, including those performed for this proposal. Although 
uncertainty exists, we believe that our approach, which used 
conservative tools and assumptions, ensures that our decisions are 
health and environmentally protective. A brief discussion of the 
uncertainties in the RTR emissions dataset, dispersion modeling, 
inhalation exposure estimates, and dose-response relationships follows 
below. Also included are those uncertainties specific to our acute 
screening assessments, multipathway screening assessments, and our 
environmental risk screening assessments. A more thorough discussion of 
these uncertainties is included in the Residual Risk Assessment for the 
Commercial Sterilization Facilities Source Category in Support of the 
Risk and Technology Review 2022 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. 
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.

[[Page 22805]]

c. Uncertainties in Inhalation Exposure Assessment
    Although every effort is made to identify all of the relevant 
facilities and emission points, as well as to develop accurate 
estimates of the annual emission rates for all relevant HAP, the 
uncertainties in our emission inventory likely dominate the 
uncertainties in the exposure assessment. Some uncertainties in our 
exposure assessment include human mobility, using the centroid of each 
census block, assuming lifetime exposure, and assuming only outdoor 
exposures. For most of these factors, there is neither an under- nor 
overestimate when looking at the maximum individual risk or the 
incidence, but the shape of the distribution of risks may be affected. 
With respect to outdoor exposures, actual exposures may not be as high 
if people spend time indoors, especially for very reactive pollutants 
or larger particles. For all factors, we reduce uncertainty when 
possible. For example, with respect to census-block centroids, we 
analyze large blocks using aerial imagery and adjust locations of the 
block centroids to better represent the population in the blocks. We 
also add additional receptor locations where the population of a block 
is not well represented by a single location.
d. Uncertainties in Dose-Response Relationships
    There are uncertainties inherent in the development of the dose-
response values used in our risk assessments for cancer effects from 
chronic exposures and noncancer effects from both chronic and acute 
exposures. Some uncertainties are generally expressed quantitatively, 
and others are generally expressed in qualitative terms. We note, as a 
preface to this discussion, a point on dose-response uncertainty that 
is stated in the EPA's 2005 Guidelines for Carcinogen Risk Assessment; 
namely, that ``the primary goal of EPA actions is protection of human 
health; accordingly, as an Agency policy, risk assessment procedures, 
including default options that are used in the absence of scientific 
data to the contrary, should be health protective'' (the EPA's 2005 
Guidelines for Carcinogen Risk Assessment, page 1-7). This is the 
approach followed here as summarized in the next paragraphs.
    Cancer UREs used in our risk assessments are those that have been 
developed to generally provide an upper bound estimate of risk. That 
is, they represent a ``plausible upper limit to the true value of a 
quantity'' (although this is usually not a true statistical confidence 
limit). In some circumstances, the true risk could be as low as zero; 
however, in other circumstances the risk could be greater. Chronic 
noncancer RfC and reference dose 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, which considers uncertainty, variability, and gaps in the 
available data. The UFs are applied to derive dose-response values that 
are intended to protect against appreciable risk of deleterious 
effects.
    Many of the UFs used to account for variability and uncertainty in 
the development of acute dose-response values are quite similar to 
those developed for chronic durations. Additional adjustments are often 
applied to account for uncertainty in extrapolation from observations 
at one exposure duration (e.g., 4 hours) to derive an acute dose-
response value at another exposure duration (e.g., 1 hour). Not all 
acute dose-response values are developed for the same purpose, and care 
must be taken when interpreting the results of an acute assessment of 
human health effects relative to the dose-response value or values 
being exceeded. Where relevant to the estimated exposures, the lack of 
acute dose-response values at different levels of severity should be 
factored into the risk characterization as potential uncertainties.
    Uncertainty also exists in the selection of ecological benchmarks 
for the environmental risk screening assessment. We established a 
hierarchy of preferred benchmark sources to allow selection of 
benchmarks for each environmental HAP at each ecological assessment 
endpoint. We searched for benchmarks for three effect levels (i.e., no-
effects level, threshold-effect level, and probable effect level), but 
not all combinations of ecological assessment/environmental HAP had 
benchmarks for all three effect levels. Where multiple effect levels 
were available for a particular HAP and assessment endpoint, we used 
all of the available effect levels to help us determine whether risk 
exists and whether the risk could be considered significant and 
widespread.
    Although we make every effort to identify appropriate human health 
effect dose-response values for all pollutants emitted by the sources 
in this risk assessment, some HAP emitted by this source category are 
lacking dose-response assessments. Accordingly, these pollutants cannot 
be included in the quantitative risk assessment, which could result in 
quantitative estimates understating HAP risk. To help to alleviate this 
potential underestimate, where we conclude similarity with a HAP for 
which a dose-response value is available, we use that value as a 
surrogate for the assessment of the HAP for which no value is 
available. To the extent use of surrogates indicates appreciable risk, 
we may identify a need to increase priority for an IRIS assessment for 
that substance. We additionally note that, generally speaking, HAP of 
greatest concern due to environmental exposures and hazard are those 
for which dose-response assessments have been performed, reducing the 
likelihood of understating risk. Further, HAP not included in the 
quantitative assessment are assessed qualitatively and considered in 
the risk characterization that informs the risk management decisions, 
including consideration of HAP reductions achieved by various control 
options.
    For a group of compounds that are unspeciated (e.g., glycol 
ethers), we conservatively use the most protective dose-response value 
of an individual compound in that group to estimate risk. Similarly, 
for an individual compound in a group (e.g., ethylene glycol diethyl 
ether) that does not have a specified dose-response value, we also 
apply the most protective dose-response value from the other compounds 
in the group to estimate risk.
e. Uncertainties in Acute Inhalation Screening Assessments
    In addition to the uncertainties highlighted above, there are 
several factors specific to the acute exposure assessment that the EPA 
conducts as part of the risk review under section 112 of the CAA. The 
accuracy of an acute inhalation exposure assessment depends on the 
simultaneous occurrence of independent factors that may vary greatly, 
such as hourly emissions rates, meteorology, and the presence of a 
person. In the acute screening assessment that we conduct under the RTR 
program, we assume that peak emissions from the source category and 
reasonable worst-case air dispersion conditions (i.e., 99th percentile) 
co-occur. We then include the additional assumption that a person is 
located at this point at the same time. Together, these assumptions 
represent a reasonable worst-case actual exposure scenario. In most 
cases, it is unlikely that a person would be located at the point of 
maximum exposure during the time when peak emissions and reasonable 
worst-case air dispersion conditions occur simultaneously.

[[Page 22806]]

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 American Meteorological Society (AMS)/Environmental 
Protection Agency (EPA) Regulatory Model (AERMOD)--that estimate 
environmental pollutant concentrations and human exposures for five PB-
HAP (dioxins/furans, POM, mercury (both inorganic and methyl mercury), 
cadmium, and arsenic) and two acid gases (HF and HCl). For lead, the 
other PB-HAP, we use AERMOD to determine ambient air concentrations, 
which are then compared to the secondary National Ambient Air Quality 
Standards 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.
    Model uncertainty concerns whether the model adequately represents 
the actual processes that might occur in the environment, such as the 
movement of a pollutant through soil or accumulation of the pollutant 
over time. This type of uncertainty is difficult to quantify. However, 
based on feedback received from previous EPA SAB reviews and other 
reviews, we are confident that the models used in the screening 
assessments are appropriate and state-of-the-art for the multipathway 
and environmental screening risk assessments conducted in support of 
RTRs.
    Input uncertainty is concerned with how accurately the models have 
been configured and parameterized for the assessment at hand. For Tier 
1 of the multipathway and environmental screening assessments, we 
configured the models to avoid underestimating exposure and risk. This 
was accomplished by selecting upper-end values from nationally 
representative datasets for the more influential parameters in the 
environmental model, including selection and spatial configuration of 
the area of interest, lake location and size, meteorology, surface 
water, soil characteristics, and structure of the aquatic food web. We 
also assume an ingestion exposure scenario and values for human 
exposure factors that represent reasonable maximum exposures.
    In Tier 2 of the multipathway and environmental screening 
assessments, we refine the model inputs to account for meteorological 
patterns in the vicinity of the facility versus using upper-end 
national values, and we identify the actual location of lakes near the 
facility rather than the default lake location that we apply in Tier 1. 
By refining the screening approach in Tier 2 to account for local 
geographical and meteorological data, we decrease the likelihood that 
concentrations in environmental media are overestimated, thereby 
increasing the usefulness of the screening assessment. In Tier 3 of the 
screening assessments, we refine the model inputs again to account for 
hour-by-hour plume-rise and the height of the mixing layer. We can also 
use those hour-by-hour meteorological data in a TRIM.FaTE run using the 
screening configuration corresponding to the lake location. These 
refinements produce a more accurate estimate of chemical concentrations 
in the media of interest, thereby reducing the uncertainty with those 
estimates. The assumptions and the associated uncertainties regarding 
the selected ingestion exposure scenario are the same for all three 
tiers.
    For the environmental screening assessment for acid gases, we 
employ a single-tiered approach. We use the modeled air concentrations 
and compare those with ecological benchmarks.
    For all tiers of the multipathway and environmental screening 
assessments, our approach to addressing model input uncertainty adopts 
conservative assumptions that are intended to be protective of public 
health. 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.

III. Analytical Results and Proposed Decisions

    In this section, we describe the analyses performed to support the 
proposed decisions for establishing standards for previously 
unregulated processes and pollutants, the residual risk assessment, the 
technology review, and other issues addressed in this proposal. We also 
describe the proposed standards that result from this series of 
analyses. To develop the proposed standards, we first determined the 
proposed standards for previously unregulated emission sources under 
CAA section 112(d)(2)-(3) (MACT) or 112(d)(5) (GACT). Next, we assessed 
the remaining risks, taking into account the current standards and the 
proposed standards we developed under the first analysis for the 
currently unregulated sources. Based on the risk assessment, we 
identified additional control options to ensure that risks are 
acceptable and provide an ample margin of safety to protect public 
health. Based on those analyses, we are proposing risk-based standards 
for certain sources under CAA section 112(f). We also conducted a 
technology review, under CAA section 112(d)(6). Finally, we evaluated 
the startup, shutdown, and malfunction (SSM) provisions; monitoring, 
recordkeeping, and reporting; and

[[Page 22807]]

performance testing requirements in the current rule, and we are 
proposing amendments to ensure consistency with the EPA's current 
approaches related to these provisions.

A. How are we proposing to define affected sources?

    We are proposing to specifically define affected sources in subpart 
O for the reasons explained below. The current subpart O does not 
contain definitions for affected sources, which means the definition of 
an ``affected source'' at 40 CFR 63.2 currently applies. 40 CFR 63.2 
defines an affected source as ``the collection of equipment, 
activities, or both within a single contiguous area and under common 
control that is included in a section 112(c) source category or 
subcategory for which a section 112(d) standard or other relevant 
standard is established pursuant to section 112 of the Act.'' 
Accordingly, an affected source under the current subpart O, as defined 
under 40 CFR 63.2, includes all SCVs and ARVs at a currently regulated 
EtO commercial sterilization facility, and the applicable standard is 
based on the facility's annual EtO usage amount. It is not clear that 
EPA had intended to apply the ``affected source'' definition at 40 CFR 
63.2 to subpart O as we did not find specific discussions on this topic 
in the prior rulemakings for subpart O. In any event, we evaluated this 
issue for purposes of the present rulemaking. For point source 
emissions (i.e., SCVs, ARVs, and CEVs), we do not believe that the 
``affected source'' definition at 40 CFR 63.2 is appropriate because a 
facility may not route all emissions from a particular type of point 
source (e.g., emissions from all SCVs at a facility) to the same 
emission control system, thus making compliance demonstration with the 
standards difficult. Therefore, for point sources, we are proposing to 
define an affected source as each individual SCV, ARV or CEV at a 
facility.\16\
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    \16\ The proposed definition, if finalized, would not apply 
retroactively and, therefore, would not be used to determine 
compliance with subpart O for periods prior to the final rule 
amending subpart O.
---------------------------------------------------------------------------

    For room air emissions, which are currently unregulated, we are 
proposing to define Group 1 and Group 2 room air emissions as a 
collection of emissions. Group 1 room air emissions would be defined as 
emissions from indoor EtO storage, EtO dispensing, vacuum pump 
operations, and pre-aeration handling of sterilized material. Group 2 
room air emissions would be defined as emissions from post-aeration 
handling of sterilized material.
    Unlike point sources, the collection of Group 1 and Group 2 
emissions described above are commonly routed to the same emission 
control and, therefore, it seems logical to define affected sources for 
room air emissions by the groupings described above. Also, the 
equipment and processes that contribute to these emissions (e.g., 
drums, pumps, sterilized material) are so numerous that defining each 
of these emissions individually as an affected source would be 
impractical and an implementation burden.
    For the reasons explained above, we are proposing to add 
definitions for affected sources to 40 CFR 63.360. Specifically, for 
SCVs, ARVs, and CEVs, we are proposing to define the affected source as 
the individual vent. For Group 1 and Group 2 room air emissions, we are 
proposing to define the affected source as the collection of all room 
air emissions for each group as described above at any sterilization 
facility. We are soliciting comment on these proposed definitions 
(Comment C-1).

B. What actions are we taking pursuant to CAA sections 112(d)(2), 
112(d)(3), and 112(d)(5)?

    In our review of the EtO Commercial Sterilization NESHAP, we 
identified emission sources of EtO that are currently unregulated and 
developed emission standards under sections 112(d)(2)-(3) or (d)(5), as 
appropriate. In addition to room air emission sources, certain point 
source emissions are also currently unregulated, including the 
following: SCVs, ARVs, and CEVs at facilities where EtO use is less 
than 1 tpy; ARVs and CEVs at facilities where EtO use is at least 1 tpy 
but less than 10 tpy; and CEVs at facilities where EtO use is at least 
10 tpy. Emission standards are being proposed for these sources under 
CAA sections 112(d)(2)-(3) or (d)(5), as appropriate. We are required 
under CAA section 112(d)(3) to establish MACT standards for major 
sources. For new sources, the MACT floor cannot be less stringent than 
the emission control that is achieved in practice by the best 
controlled similar source. For existing sources, the MACT floor cannot 
be less stringent than the average emission limitation achieved by the 
best performing 12 percent of existing sources for which data are 
available for source categories with 30 or more sources, or the best 
performing 5 sources for source categories with fewer than 30 sources. 
For area source facilities, CAA section 112(d)(5) gives EPA discretion 
to set standards based on GACT for those facilities in lieu of MACT 
standards. Unlike MACT, there is no prescription in CAA section 
112(d)(5) that standards for existing sources must, at a minimum, be 
set at the level of emission reduction achieved by the best performing 
12 percent of existing sources, or that standards for new sources be 
set at the level of emission reduction achieved in practice by the best 
controlled similar source. The legislative history suggests that 
standards under CAA section 112(d)(5) should ``[reflect] application of 
generally available control technology that is, methods, practices, and 
techniques which are commercially available and appropriate for 
application by the sources in the category considering economic impacts 
and the technical capabilities of the firms to operate and maintain the 
emissions control systems.'' SEN. REP. NO. 101-228, at 171 (1989). 
Thus, in contrast to MACT, CAA section 112(d)(5) allows us to consider 
various factors in determining the appropriate standard for a given 
area source category.
    We are proposing to set EtO standards for unregulated emissions at 
new and existing major and area sources as authorized by the CAA.\17\ 
In deciding how to regulate currently unregulated emissions from 
existing area source facilities, we are proposing that, in all cases, 
setting GACT standards would be appropriate because (1) a significant 
portion of the area source facilities are owned by small entities, (2) 
companies could experience significant economic burden (i.e., cost-to-
sales ratio exceeding 5 percent) if MACT standards are imposed, (3) we 
are trying to minimize disruptions to the supply of medical devices and 
thereby avoid creating a potential health concern, and (4) as discussed 
in more detail below in section III.D, we are proposing revision to the 
standards, including those being proposed under CAA section 112(d)(5) 
for certain currently unregulated emission sources, based on our 
assessment of the post-control risks under CAA section 112(f)(2) in 
this proposed rulemaking.
---------------------------------------------------------------------------

    \17\ Some facilities also use propylene oxide (PpO) when 
conducting sterilization operations. The only facilities that 
reported PpO emissions were area source facilities. PpO is not one 
of the 30 urban HAP listed for regulation under CAA section 
112(c)(3)/(k)(3)(B), an obligation that EPA completed in 2011 (76 FR 
15308). Further, as mentioned earlier, area sources of commercial 
sterilizers were listed for regulation under CAA section 112(c)(3) 
based on a finding of threat of adverse effects from commercial 
sterilizers using EtO. We are therefore not proposing standards for 
PpO.
---------------------------------------------------------------------------

    CAA section 112(a) defines a major source as ``any stationary 
source or group of stationary sources located within a contiguous area 
and under

[[Page 22808]]

common control that emits or has the potential to emit considering 
controls, in the aggregate, 10 tpy or more of any HAP or 25 tpy or more 
of any combination of HAPs. . .''. It further defines an area source as 
``any stationary source of HAPs that is not a major source''. A 
synthetic area source facility is one that otherwise has the potential 
to emit HAPs in amounts that are at or above those for major sources of 
HAP, but that have taken a restriction so that its potential to emit is 
less than such amounts for major sources. For the facilities within 
this source category, EtO sterilization tends to be either the primary 
or only activity and source of HAP emissions. In addition, most of the 
EtO used at these facilities is released through the SCV and ARV. As 
discussed in more detail below, the current subpart O contains 
standards for certain point sources at facilities where EtO use is at 
least 10 tpy. Some state and local governments also regulate EtO 
emissions from these facilities. Based on these facts, as well as our 
review of the permits, we believe that all facilities that use more 
than 10 tpy are synthetic area source facilities, and all but one 
facility where EtO use is less than 10 tpy are true area source 
facilities. We have only identified one facility where EtO use is less 
than 10 tpy that is a major source due to other HAP emissions, which 
are regulated under other section 112 NESHAP.\18\
---------------------------------------------------------------------------

    \18\ This facility is also subject to 40 CFR part 63, subparts 
Q, JJJJ, and ZZZZ.
---------------------------------------------------------------------------

1. SCVs at Facilities Where EtO Use Is Less Than 1 Tpy
a. Existing Sources
    The current subpart O does not contain emission standards for SCVs 
at facilities where EtO use is less than 1 tpy. There are 20 facilities 
where EtO use is less than 1 tpy, all of which have SCVs. Of these 20 
facilities, 19 are currently controlling their SCV emissions. Fourteen 
of these facilities use catalytic oxidizers, five use gas/solid 
reactors, and one uses an acid-water scrubber and gas/solid reactor in 
series. Note that this does not sum up to 19 because one facility is 
using two different types of control systems to reduce SCV emissions. 
Performance tests are available for SCVs at three facilities where EtO 
use is less than 1 tpy; two of these facilities use catalytic 
oxidizers, and one uses a gas/solid reactor. We reviewed all these 
performance tests, and the reported emission reductions range from 98.6 
to 99.9 percent.
    For existing sources, we considered two potential GACT options for 
reducing EtO emissions from this group: the first option considers 
setting an emission standard that reflects the use of emission controls 
on the SCVs, and the second option considers applying a best management 
practice (BMP) to reduce EtO use per sterilization cycle (i.e., 
pollution prevention). With respect to the first option, because 19 out 
of 20 facilities with SCVs and EtO usage less than 1 tpy are already 
using controls to reduce SCV emissions, we consider emission controls 
to be generally available for SCVs. We considered a standard of 99 
percent emission reduction, which is the current subpart O standard for 
SCVs at facilities where EtO use is at least 1 tpy. We find this 
standard to be reasonable for existing SCVs at facilities using less 
than 1 tpy EtO because it is comparable to the emission reductions 
shown in the performance tests from facilities within this group.
    The second potential GACT option we considered was a management 
practice that would require facilities to follow either the Cycle 
Calculation Approach or the Bioburden/Biological Indicator Approach to 
achieve sterility assurance in accordance with International 
Organization for Standardization (ISO) 11135:2014 and ISO 11138-1:2017. 
ISO 11135:2014 describes these two approaches. Currently, ISO 
11135:2014 is a voluntary consensus standard for EtO sterilization that 
is recognized by FDA.\19\ ISO 11135:2014 ``describes requirements that, 
if met, will provide an EtO sterilization process intended to sterilize 
medical devices, which has appropriate microbicidal activity.'' \20\ 
ISO 11138-1:2017 ``specifies general requirements for production, 
labelling, test methods and performance characteristics of biological 
indicators, including inoculated carriers and suspensions, and their 
components, to be used in the validation and routine monitoring of 
sterilization processes''.\21\ The EPA has learned, through 
conversations with industry stakeholders, that current EtO use is based 
on very conservative estimates of the amount of EtO needed to achieve 
sterility and that current EtO use could be reduced by as much as 50 
percent while still meeting sterility standards.\22\ We therefore 
project that this BMP, which would require facilities to follow either 
the Cycle Calculation Approach or the Bioburden/Biological Indicator 
Approach to achieve sterility assurance in accordance ISO 11135:2014 
and ISO 11138-1:2017, would achieve those 50 percent reductions. We 
consider this option to be generally available because facilities 
already must configure sterilization cycles in accordance with ISO 
11135:2014 and ISO 11138-1:2017. Option 2 would simply require that 
they follow either the Cycle Calculation Approach or the Bioburden/
Biological Indicator Approach to meet sterility assurance according to 
the ISO standards. These methods can use 50 percent less EtO than the 
most conservative method, Half Cycle Approach, which is currently the 
common industry practice.
---------------------------------------------------------------------------

    \19\ FDA also recognizes ISO 11138-1:2017, which remains current 
per ISO. See https://www.iso.org/standard/66442.html.
    \20\ ISO 11135:2014, Sterilization of health-care products--
Ethylene oxide--Requirements for the development, validation and 
routine control of a sterilization process for medical devices, July 
2014.
    \21\ ISO 11138-1:2017, Sterilization of health care products--
Biological indicators--Part 1: General Requirements, March 2017.
    \22\ See memorandum, Meeting Minutes for Discussion with 
Representative of STERIS, located at Docket ID No. EPA-HQ-OAR-2019-
0178. September 18, 2019.
---------------------------------------------------------------------------

    The impacts of the two potential GACT options are presented in 
Table 5.

  Table 5--Nationwide Emissions Reductions and Cost Impacts of Options Considered Under CAA Section 112(d)(5) for Existing SCVs at Facilities Where EtO
                                                                 Use Is Less Than 1 TPY
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                           EtO emission        Cost
                 Option                         Proposed standard          Total capital     Total annual costs ($/yr)      reductions     effectiveness
                                                                          investment ($)                                       (tpy)        ($/ton EtO)
--------------------------------------------------------------------------------------------------------------------------------------------------------
1......................................  99 percent emission reduction..         $92,211  $21,762.......................          3.3E-2        $654,578

[[Page 22809]]

 
2......................................  BMP (estimated 50 percent                     0  870,000 (one-time annual cost)            0.24       3,678,138
                                          emission reduction).                             \1\.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ This includes the cost for testing to verify that the new sterilization process complies with ISO 11135:2014 and ISO 11138-1:2017, as well as re-
  submitting to FDA for approval. It is expected that facilities will only incur this cost once and it is assumed to be incurred in the first year of
  compliance, but it is treated as an annual cost for the purposes of estimating total annual costs (i.e., annualized capital costs plus annual costs)
  in the analysis.

    Based on the estimates above, we find both options to be cost 
effective. While the cost-effectiveness number for Option 2 may seem 
high, EtO is a highly potent carcinogen, and the cost-effectiveness of 
Option 2 is within the range of the values that we have determined to 
be cost-effective for highly toxic HAPs. This includes hexavalent 
chromium, where we finalized a requirement with a cost-effectiveness of 
$15,000/lb ($30,000,000/ton) for existing small hard chromium 
electroplating to provide an ample margin of safety (taking into 
account cost among other factors) (77 FR 58227-8, 58239). While both 
options are considered generally available under CAA section 112(d)(5), 
Option 1 would ensure that facilities that are currently reducing 
emissions from SCVs using emission controls would continue to do so, 
whereas Option 2 would allow these facilities to remove their existing 
controls and potentially increase their emissions from SCVs. As 
mentioned earlier, 19 out of 20 facilities where EtO use is less than 1 
tpy are currently controlling their SCV emissions. Therefore, the EtO 
emission reductions that occur because of Option 1 are relatively 
small. However, if 99 percent emission reduction were applied to 
uncontrolled emissions, the EtO emission reductions would be 7.4 tpy. 
In addition, Option 1 would incur fewer annual costs than Option 2. 
Therefore, pursuant to CAA section 112(d)(5), we are proposing Option 1 
for existing SCVs at facilities where EtO use is less than 1 tpy. 
Specifically, we are proposing to require these facilities to 
continuously reduce emissions from existing SCVs by 99 percent. We 
solicit comment on the proposed standard (Comment C-2).
    We solicit comment on whether to also adopt an alternative emission 
limit that reflects 99 percent emission reduction from SCVs for the 
following reason. There may be a point where the amount of EtO usage is 
so low that it may become difficult to demonstrate compliance with the 
proposed 99 percent emission reduction standard if available 
measurement instruments are not low enough to detect the resulting 
emissions post-control. To alleviate this problem, we considered 
establishing an alternative standard in a pounds per hour (lb/hr) 
emission rate format but recognized that the same detection issue may 
exist with such alternative standard for some facilities, as explained 
in section III.B.5 of this preamble. We solicit comment on whether to 
include such an alternative equivalent standard because we think 
sources most likely can demonstrate compliance with one or the other 
standard (Comment C-3). We also solicit comment on how to establish 
such an equivalent emission limit. We calculated the emission rate by 
first assuming that all of these facilities are achieving the emission 
reduction standard (i.e., 99 percent reduction). The emission rate at 
each facility is dependent on EtO usage, the portion of EtO usage that 
is emitted from the SCVs, and the performance of the control device, if 
used. We then calculated the sum of SCV emissions at facilities where 
EtO use is less than 1 tpy by the total number of SCVs at these 
facilities, and rounded to two significant figures, which resulted in 
2.5E-4 lb/hr. We solicit comment on whether 2.5E-4 lb/hr is equivalent 
to 99 percent reduction and whether the method described above used to 
calculate this lb/hr limit is appropriate for calculating an emission 
limit equivalent to a percentage emission reduction standard (Comment 
C-4).
    We are aware that requiring facilities to follow either the Cycle 
Calculation Approach or the Bioburden/Biological Indicator Approach to 
achieve sterility assurance in accordance with ISO 11135:2014 and ISO 
11138-1:2017 may reduce the number of products that can be sterilized 
simultaneously. This may result in lower EtO emission reductions, 
bottlenecks in the medical device supply chain, and facilities having 
to invest in additional chambers and staff. In addition, the 
revalidation of sterilization cycles is a time-intensive process and 
could also worsen potential bottlenecks in the medical device supply 
chain. We also understand that this requirement may interfere with the 
ongoing FDA Innovation Challenges, which are aimed at producing EtO 
alternatives \23\ and reducing overall EtO use in sterilization.\24\ 
Therefore, we solicit comment on several aspects of this requirement, 
including the true effectiveness of this requirement on reducing EtO 
emissions, any capital and annual costs that we did not account for, 
the time that is needed to comply with this requirement, and any other 
potential barriers to or impacts of imposing this requirement (Comment 
C-5). We are also aware of other BMPs that may reduce EtO emissions, 
including a limit on EtO concentration within each sterilization 
chamber, as well as restrictions on packaging and pallet material. 
Based on responses to the December 2019 questionnaire and September 
2021 ICR (OMB Control No. 2060-0733), we understand that the average 
EtO concentration within the chamber during sterilization is 600 
milligrams per liter (mg/L). Considering the number of cycles that are 
conducted in each chamber per year, as well as the volume of the 
chambers themselves, we believe that limiting the EtO concentration 
within each sterilization chamber to 290 mg/L would reduce EtO 
emissions by 50 percent. We solicit comment on the effectiveness of 
limiting the EtO concentration within each sterilization chamber on EtO 
emissions, what that limit might be, the decision criteria for 
determining that limit, any capital and annual costs associated with 
that limit, the time needed to comply with that limit, and any other 
potential barriers to or consequences of imposing that limit (Comment 
C-6). Our understanding of the impact of packaging and pallet material 
on EtO emissions is mostly

[[Page 22810]]

limited to one study conducted by a commercial EtO sterilizer.\25\ 
However, the study did conclude that packaging and pallet materials do 
have an impact on EtO retention and, by extension, emissions. In 
addition, it is our understanding that reducing paper packaging (and 
replacing with electronic barcodes) may aid in the reduction of EtO 
emissions. We solicit comment on the effectiveness of limiting 
packaging and pallet materials on EtO emissions, what those limits 
might be, the decision criteria for determining those limits, any 
capital and annual costs associated with those limits, the time needed 
to comply with those limits, and any other potential barriers to or 
consequences of imposing those limits (Comment C-7).
---------------------------------------------------------------------------

    \23\ https://www.fda.gov/medical-devices/general-hospital-devices-and-supplies/fda-innovation-challenge-1-identify-new-sterilization-methods-and-technologies.
    \24\ https://www.fda.gov/medical-devices/general-hospital-devices-and-supplies/fda-innovation-challenge-2-reduce-ethylene-oxide-emissions.
    \25\ See memorandum, Engineering Studies Report, located at 
Docket ID No. EPA-HQ-OAR-2019-0178. April 30, 2020.
---------------------------------------------------------------------------

    We note that, as part of the pesticide registration review required 
under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), 
the EPA is concurrently issuing Proposed Interim Decision (PID) for EtO 
that includes use rate reduction. While the proposed CAA NESHAP and the 
FIFRA PID are based on different statutory authorities and mandates, 
they complement each other in their shared objective of preventing 
overuse of EtO in achieving sterility. The proposed actions are also 
complementary in that they are intended to reduce public health risks 
from EtO exposure. The proposed CAA rulemaking focuses on reducing EtO 
emissions to outside air from commercial sterilization facilities, in 
order to reduce risk to people living near those facilities (called 
``residential bystanders'' in FIFRA). The FIFRA PID would also reduce 
EtO risk to people outside sterilization facilities, including 
residential and non-residential bystanders (i.e., those who go to work 
or school near facilities), as well as risks to workers exposed to EtO 
inside sterilization facilities.
b. New Sources
    For new SCVs at facilities where EtO use is less than 1 tpy, we 
considered two potential GACT options similar to those evaluated for 
existing SCVs at facilities where EtO use is less than 1 tpy for the 
same reasons explained above. The first potential GACT option would 
require achieving 99 percent emission reduction. The second potential 
GACT option we considered is a BMP described in section III.B.1.a of 
this preamble, which would require facilities to follow either the 
Cycle Calculation Approach or the Bioburden/Biological Indicator 
Approach to achieve sterility assurance in accordance with ISO 
11135:2014 and ISO 11138-1:2017. The impacts of these options, which 
are presented in Table 6 of this preamble, are based on a model plant 
for new SCVs at a facility using less than 1 tpy EtO with the following 
assumptions reflecting the average of each of the parameters at 
existing facilities using less than 1 tpy EtO:
     Number of SCVs: 5.
     Annual EtO use: 0.39 tpy.
     Annual operating hours: 6,000.
     Portion of EtO going to SCVs: 97.47 percent.
     SCV flow rate: 30 cubic feet per second (cfs).
     Number of unique cycles: 1.

 Table 6--Model Plant Emissions Reduction and Cost Impacts of Options Considered Under CAA Section 112(d)(5) for New SCVs at Facilities Where EtO Use Is
                                                                     Less Than 1 TPY
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                           EtO emission        Cost
                 Option                         Proposed standard          Total capital     Total annual costs ($/yr)      reductions     effectiveness
                                                                          investment ($)                                       (tpy)        ($/ton EtO)
--------------------------------------------------------------------------------------------------------------------------------------------------------
1......................................  99 percent emission reduction..         $92,211  $60,056.......................            0.37        $161,105
2......................................  BMP (estimated 50 percent                     0  30,000 (one-time annual cost)             0.19         159,344
                                          emission reduction).                             \1\.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ This includes the cost for testing to verify that the new sterilization process complies with ISO 11135:2014 and ISO 11138-1:2017, as well as re-
  submitting to FDA for approval. It is expected that facilities will only incur this cost once and it is assumed to be incurred in the first year of
  compliance, but it is treated as an annual cost for the purposes of estimating total annual costs (i.e., annualized capital costs plus annual costs)
  in the analysis.

    Based on the estimates above, we find both options to be cost-
effective. While both options are considered generally available under 
CAA section 112(d)(5), Option 1 would achieve greater emission 
reductions than Option 2. Therefore, pursuant to CAA section 112(d)(5), 
we are proposing to establish a standard for new SCVs at facilities 
where EtO use is less than 1 tpy under CAA section 112(d)(5). 
Specifically, we are proposing to require these facilities to 
continuously reduce emissions from existing SCVs by 99 percent. We are 
soliciting comment on this proposed standard (Comment C-8). In 
addition, for the same reason discussed in section III.B.1.a of this 
preamble, we solicit comment on whether to include an alternative lb/hr 
limit that is equivalent to 99 percent emission reduction for new SCVs 
at facilities using less than 1 tpy and whether 2.5E-4 lb/hr, which we 
calculated using the method described in section III.B.1.a, is an 
appropriate alternative standard that is equivalent to the proposed 99 
percent emission reduction standard for new SCVs at facilities using 
less than 1 tpy (Comment C-9).
2. ARV at Facilities Where EtO Use Is at Least 10 Tpy
    We first note that, unlike the other point sources discussed in 
this section of the preamble, ARV at facilities where EtO use is at 
least 10 tpy are currently regulated in subpart O. See 40 CFR 
63.362(d). However, we are proposing corrections to this standard 
because we believe, for the following reasons, that the current 
standard is inconsistent with the requirements of CAA section 112. The 
current standard, 40 CFR 63.362(d), is a MACT standard applicable to 
facilities where EtO use is at least 10 tpy, which include major 
sources of HAP (59 FR 10597). It requires these facilities to either 
achieve 99 percent emission reduction or limit the outlet concentration 
to a maximum of 1 part-per-million by volume (ppmv), ``whichever is 
less stringent, from each aeration room vent.'' While a MACT standard 
may be expressed in multiple formats so long as they are equivalent, 
the phrase ``whichever is less stringent'' in 40 CFR 63.362(d) suggests 
that these two formats are not equivalent. Further, a MACT standard 
cannot allow compliance with a less stringent alternative standard, 
which in this case is the 1 ppmv limit. As explained

[[Page 22811]]

below, we determined that the equivalent outlet concentration to a 99 
percent emission reduction is 0.5 ppmv. To determine the equivalent ARV 
outlet EtO concentration, the EPA reviewed all available facility 
information for ARVs at facilities where EtO use is at least 10 tpy. We 
calculated the outlet EtO concentration that is equivalent to 99 
percent removal efficiency for ARVs at facilities where EtO use is at 
least 10 tpy by first assuming that all of these facilities are 
achieving the removal efficiency standard. The outlet EtO concentration 
at each facility is dependent on EtO usage, the portion of EtO usage 
that is emitted from the ARVs, and the flowrate and temperature of the 
ARV. We then calculated the ARV outlet EtO concentration at each 
facility, calculated the average value of the ARV outlet EtO 
concentrations across all facilities, and rounded to one significant 
figure, which resulted in 0.5 ppmv.
    In light of the above, we are proposing to remove the less 
stringent 1 ppmv concentration alternative for ARVs at facilities where 
EtO use is at least 10 tpy. We solicit comment on removing this 
alternative concentration standard for ARVs at facilities where EtO use 
is at least 10 tpy (Comment C-10).
3. ARV at Facilities Where EtO Use Is at Least 1 Tpy But Less Than 10 
Tpy
a. Existing Sources
    The current subpart O does not contain emission standards for ARVs 
at facilities where EtO use is at least 1 tpy but less than 10 tpy. 
There are 18 facilities where EtO use is at least 1 tpy but less than 
10 tpy, 10 of which have ARVs. Of these 10 facilities, nine are 
currently controlling their ARV emissions. Five of these facilities use 
catalytic oxidizers, two use gas/solid reactors, one uses a wet 
scrubber, and one uses a gas/solid reactor and catalytic oxidizer in 
series. Performance tests are available for ARVs at four facilities 
where EtO use is at least 1 tpy but less than 10 tpy. Two of these 
facilities use catalytic oxidizers, and two use gas/solid reactors. We 
reviewed all these performance tests, and the reported emission 
reductions ranged from 99.1 to 99.99 percent.
    For existing sources, we considered two potential GACT options for 
reducing EtO emissions from this group: the first option reflects the 
use of emission controls on the ARVs, and the second option reflects 
applying a BMP to reduce EtO use per sterilization cycle (i.e., 
pollution prevention). With respect to the first option, because nine 
out of 10 facilities with ARVs and EtO usage at least 1 tpy but less 
than 10 tpy are already using controls to reduce ARV emissions, we 
consider emission controls to be generally available for existing ARVs. 
We considered a standard of 99 percent emission reduction, which is the 
current subpart O standard for ARVs at facilities where EtO use is at 
least 10 tpy. We find this standard to be reasonable for existing ARVs 
at facilities using at least 1 tpy but less than 10 tpy EtO because it 
is comparable to the emission reductions shown in the performance tests 
from facilities within this group. The second potential GACT option we 
considered was the same management practice discussed in section 
III.B.1.a, which would require facilities to follow either the Cycle 
Calculation Approach or the Bioburden/Biological Indicator Approach to 
achieve sterility assurance in accordance with ISO 11135:2014 and ISO 
11138-1:2017. During the sterilization process, EtO becomes trapped 
within the material and continues to off-gas after the sterilization 
process is complete. Therefore, if less EtO is used during the 
sterilization process, this can lead to a reduction in post-
sterilization EtO emissions.
    The impacts of the potential GACT options are presented in Table 7.

Table 7--Nationwide Emissions Reduction and Cost Impacts of Options Considered Under CAA Section 112(d)(5) for Existing ARVs at Facilities Where EtO Use
                                                         Is at Least 1 TPY But Less Than 10 TPY
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                           EtO emission        Cost
                 Option                         Proposed standard          Total capital     Total annual costs ($/yr)      reductions     effectiveness
                                                                          investment ($)                                       (tpy)        ($/ton EtO)
--------------------------------------------------------------------------------------------------------------------------------------------------------
1......................................  99 percent emission reduction..      $1,290,957  $327,530......................            0.13      $2,597,271
2......................................  BMP (estimated 50 percent                     0  840,000 (one-time annual cost)          7.2E-2      11,633,666
                                          emission reduction).                             \1\.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ This includes the cost for testing to verify that the new sterilization process complies with ISO 11135:2014 and ISO 11138-1:2017, as well as re-
  submitting to FDA for approval. It is expected that facilities will only incur this cost once and it is assumed to be incurred in the first year of
  compliance, but it is treated as an annual cost for the purposes of estimating total annual costs (i.e., annualized capital costs plus annual costs)
  in the analysis.

    Based on the estimates above, we find both options to be cost 
effective. While these cost-effectiveness numbers may seem high, EtO is 
a highly potent carcinogen, and the cost-effectiveness numbers of these 
options are within the range of the values that we have determined to 
be cost-effective for highly toxic HAPs. We are proposing Option 1 for 
the following reasons. First, while both options are considered 
generally available under CAA section 112(d)(5), Option 1 would achieve 
much greater emission reduction than Option 2. Second, Option 1 would 
ensure that facilities that are currently reducing emissions from ARVs 
using emission controls would continue to do so, whereas Option 2 would 
allow these facilities to remove their existing controls and 
potentially increase their emissions from ARVs. Third, Option 1 would 
incur fewer annual costs than Option 2. Therefore, pursuant to CAA 
section 112(d)(5), we are proposing Option 1 for existing ARVs at 
facilities where EtO use is at least 1 tpy but less than 10 tpy. 
Specifically, we are proposing to require these facilities to 
continuously reduce emissions from existing ARVs by 99 percent. We 
solicit comment on these proposed standards. In addition, we solicit 
comment on several aspects of this requirement, including the true 
effectiveness of this requirement on reducing EtO emissions, any 
capital and annual costs that we did not account for, the time that is 
needed to comply with this requirement, and any other potential 
barriers to or impacts of imposing this requirement (Comment C-11). In 
addition, for the same reason discussed above in section III.B.1.a, we 
solicit comment on whether to include an alternative lb/hr limit that 
is equivalent to 99 percent emission reduction for existing ARVs at 
facilities where EtO use is at least 1 tpy but less than 10 tpy and 
whether 2.1E-4 lb/hr, which we calculated using the method described in 
section III.B.1.a, is an appropriate alternative standard that is 
equivalent to the proposed 99 percent emission reduction standard for 
existing

[[Page 22812]]

ARVs at facilities where EtO use is at least 1 tpy but less than 10 tpy 
(Comment C-12).
b. New Sources
    For new ARVs at facilities where EtO use is at least 1 tpy but less 
than 10 tpy, we considered two potential GACT options similar to those 
evaluated for existing ARVs at facilities where EtO use is at least 1 
tpy but less than 10 tpy for the same reasons explained above. The 
first potential GACT option would require achieving 99 percent emission 
reduction. The second potential GACT option we considered is a BMP 
described in section III.B.1.a of this preamble, which would require 
facilities to follow either the Cycle Calculation Approach or the 
Bioburden/Biological Indicator Approach to achieve sterility assurance 
in accordance with ISO 11135:2014 and ISO 11138-1:2017. The impacts of 
these options, which are presented in Table 8 of this preamble, are 
based on a model plant for new ARVs at a new facility using at least 1 
tpy but less than 10 tpy EtO with the following assumptions reflecting 
the average of each of the parameters at existing facilities where both 
ARVs are present and EtO use is at least 1 tpy but less than 10 tpy:
     Number of ARVs: four.
     Annual EtO use: 6 tpy.
     Annual operating hours: 6,000.
     Portion of EtO going to ARVs: 3.23 percent.
     ARV flow rate: 63 cfs.
     Number of unique cycles: three.

 Table 8--Model Plant Emissions Reduction and Cost Impacts of Options Considered Under CAA Section 112(d)(5) for New ARVs at Facilities Where EtO Use Is
                                                           at Least 1 TPY But Less Than 10 TPY
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                           EtO emission        Cost
                 Option                         Proposed standard          Total capital     Total annual costs ($/yr)      reductions     effectiveness
                                                                          investment ($)                                       (tpy)        ($/ton EtO)
--------------------------------------------------------------------------------------------------------------------------------------------------------
1......................................  99 percent emission reduction..        $184,422  $64,530.......................            0.19        $336,823
2......................................  BMP (estimated 50 percent                     0  90,000 (one-time annual cost)           9.7E-2         930,144
                                          emission reduction).                             \1\.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ This includes the cost for testing to verify that the new sterilization process complies with ISO 11135:2014 and ISO 11138-1:2017, as well as re-
  submitting to FDA for approval. It is expected that facilities will only incur this cost once and it is assumed to be incurred in the first year of
  compliance, but it is treated as an annual cost for the purposes of estimating total annual costs (i.e., annualized capital costs plus annual costs)
  in the analysis.

    Based on the estimates above, we find both options to be cost 
effective. While both options are considered generally available under 
CAA section 112(d)(5), Option 1 would achieve greater emission 
reductions and would incur fewer annual costs than Option 2. Therefore, 
pursuant to CAA section 112(d)(5), we are proposing to establish 
standards for new ARVs at facilities where EtO use is at least 1 tpy 
but less than 10 tpy under CAA section 112(d)(5). Specifically, we are 
proposing to require these facilities to continuously reduce emissions 
from existing ARVs by 99 percent. We are soliciting comment on this 
proposed standard. In addition, we solicit comment on several aspects 
of this requirement, including the true effectiveness of this 
requirement on reducing EtO emissions, any capital and annual costs 
that we did not account for, the time that is needed to comply with 
this requirement, and any other potential barriers to or impacts of 
imposing this requirement (Comment C-13). In addition, for the same 
reason discussed in section III.B.1.a of this preamble, we solicit 
comment on whether to include an alternative lb/hr limit that is 
equivalent to 99 percent emission reduction for new ARVs at facilities 
where EtO use is at least 1 tpy but less than 10 tpy and whether 1.6E-4 
lb/hr, which we calculated using the method described in section 
III.B.1.a, is an appropriate alternative standard that is equivalent to 
the proposed 99 percent emission reduction standard for new ARVs at 
facilities where EtO use is at least 1 tpy but less than 10 tpy 
(Comment C-14).
4. ARV at Facilities Where EtO Use Is Less Than 1 Tpy
a. Existing Sources
    The current subpart O does not contain emission standards for ARVs 
at facilities where EtO use is less than 1 tpy. There are 20 facilities 
where EtO use is less than 1 tpy, four of which have ARVs. Of these 
four facilities, two are currently controlling their ARV emissions. 
Both of these facilities use catalytic oxidizers. There are no 
performance tests are available for ARVs at facilities where EtO use is 
less than 1 tpy.
    For existing sources, we considered two potential GACT options for 
reducing EtO emissions from this group: the first option considers 
setting an emission standard that reflects the use of emission controls 
on the ARVs, and the second option considers applying the BMP described 
in section III.B.1.a to reduce EtO use per sterilization cycle. With 
respect to the first option, because control of ARV emissions is common 
at facilities using 1 or more tpy of EtO as explained above, and two 
out of four facilities with ARVs and EtO usage less than 1 tpy are 
already using controls to reduce ARV emissions, we consider emission 
controls to be generally available for existing ARVs at facilities with 
less than 1 tpy EtO usage. We don't have reason to believe that the 
remaining two facilities cannot use control to reduce their ARV 
emissions. We considered a standard of 99 percent emission reduction, 
which is the current subpart O standard for ARVs at facilities where 
EtO use is at least 10 tpy. While there are no performance test data 
from the four facilities with ARV and EtO usage less than 1 tpy, 
available performance data from other facilities with ARVs all indicate 
that controls can reduce ARV emissions by 99 percent, as described 
above. The second potential GACT option we considered was the 
management practice described in section III.B.1.a, which would require 
facilities to follow either the Cycle Calculation Approach or the 
Bioburden/Biological Indicator Approach to achieve sterility assurance 
in accordance with ISO 11135:2014 and ISO 11138-1:2017.
    The impacts of the two options are presented in Table 9.

[[Page 22813]]



 Table 9--Nationwide Emissions Reduction and Cost Impacts of Option Considered Under CAA Section 112(d)(5) for Existing ARVs at Facilities Where EtO Use
                                                                   Is Less Than 1 TPY
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                           EtO emission        Cost
                 Option                         Proposed standard          Total capital     Total annual costs ($/yr)      reductions     effectiveness
                                                                          investment ($)                                       (tpy)        ($/ton EtO)
--------------------------------------------------------------------------------------------------------------------------------------------------------
1......................................  99 percent emission reduction..        $184,422  $72,633.......................          2.3E-2      $3,094,182
2......................................  BMP (estimated 50 percent                     0  210,000 (one-time annual cost)          1.2E-2      17,541,860
                                          emission reduction).                             \1\.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ This includes the cost for testing to verify that the new sterilization process complies with ISO 11135:2014 and ISO 11138-1:2017, as well as re-
  submitting to FDA for approval. It is expected that facilities will only incur this cost once and it is assumed to be incurred in the first year of
  compliance, but it is treated as an annual cost for the purposes of estimating total annual costs (i.e., annualized capital costs plus annual costs)
  in the analysis.

    Based on the estimates above, we find both options to be cost 
effective. While these cost-effectiveness numbers may seem high, EtO is 
a highly potent carcinogen, and the cost-effectiveness numbers of these 
options are within the range of the values that we have determined to 
be cost-effective for highly toxic HAPs. We are proposing Option 1 for 
the following reasons. First, while both options are considered 
generally available under CAA section 112(d)(5), Option 1 would achieve 
greater emission reduction than Option 2. Second, Option 1 would ensure 
that facilities that are currently reducing emissions from ARVs using 
emission controls would continue to do so, whereas Option 2 would allow 
these facilities to remove their existing controls and potentially 
increase their emissions from ARVs. Third, Option 1 would incur fewer 
annual costs than Option 2. Therefore, pursuant to CAA section 
112(d)(5), we are proposing Option 1 for existing ARVs at facilities 
where EtO use is less than 1 tpy. Specifically, we are proposing to 
require these facilities to continuously reduce emissions from existing 
ARVs by 99 percent. We solicit comment on this proposed standard. In 
addition, we solicit comment on several aspects of this requirement, 
including the true effectiveness of this requirement on reducing EtO 
emissions, any capital and annual costs that we did not account for, 
the time that is needed to comply with this requirement, and any other 
potential barriers to or impacts of imposing this requirement (Comment 
C-15). In addition, for the same reason discussed in section III.B.1.a 
of this preamble, we solicit comment on whether to include an 
alternative lb/hr limit that is equivalent to 99 percent emission 
reduction for existing ARVs at facilities where EtO use is less than 1 
tpy and whether 5.6E-6 lb/hr, which we calculated using the method 
described in section III.B.1.a, is an appropriate alternative standard 
that is equivalent to the proposed 99 percent emission reduction 
standard for existing ARVs at facilities where EtO use is less than 1 
tpy (Comment C-16).
b. New Sources
    For new ARVs at facilities where EtO use is less than 1 tpy, we 
considered two potential GACT options similar to those evaluated for 
existing ARVs at facilities where EtO use is less than 1 tpy for the 
same reasons explained above. The first potential GACT option would 
require achieving 99 percent emission reduction. The second potential 
GACT option we considered is the BMP described in section III.B.1.a, 
which would require facilities to follow either the Cycle Calculation 
Approach or the Bioburden/Biological Indicator Approach to achieve 
sterility assurance in accordance with ISO 11135:2014 and ISO 11138-
1:2017. The impacts of these options, which are presented in Table 10 
of this preamble, are based on a model plant for new ARVs at a new 
facility using less than 1 tpy EtO with the following assumptions 
reflecting the average of each of the parameters at existing facilities 
where both ARVs are present and EtO use is less than 1 tpy EtO:
     Number of ARVs: eight.
     Annual EtO use: 0.34 tpy.
     Annual operating hours: 6,800.
     Portion of EtO going to ARVs: 4 percent.
     ARV flow rate: 4 cfs.
     Number of unique cycles: two.

Table 10--Model Plant Emissions Reduction and Cost Impacts of Options Considered Under CAA Section 112(d)(5) for New ARVs at Facilities Where EtO Use Is
                                                                     Less Than 1 TPY
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                           EtO emission        Cost
                 Option                         Proposed standard          Total capital     Total annual costs ($/yr)      reductions     effectiveness
                                                                          investment ($)                                       (tpy)        ($/ton EtO)
--------------------------------------------------------------------------------------------------------------------------------------------------------
1......................................  99 percent emission reduction..         $92,211  $37,829.......................          1.5E-2      $2,549,177
2......................................  BMP (estimated 50 percent                     0  60,000 (one-time annual cost)           7.5E-3       8,005,582
                                          emission reduction).                             \1\.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ This includes the cost for testing to verify that the new sterilization process complies with ISO 11135:2014 and ISO 11138-1:2017, as well as re-
  submitting to FDA for approval. It is expected that facilities will only incur this cost once and it is assumed to be incurred in the first year of
  compliance, but it is treated as an annual cost for the purposes of estimating total annual costs (i.e., annualized capital costs plus annual costs)
  in the analysis.

    Based on the estimates above, we find both options to be cost 
effective. While these cost-effectiveness numbers may seem high, EtO is 
a highly potent carcinogen, and the cost-effectiveness numbers of these 
options are within the range of the values that we have determined to 
be cost-effective for highly toxic HAPs. While both options are 
considered generally available under CAA section 112(d)(5), Option 1 
would achieve greater emission reductions and would incur fewer annual 
costs than Option 2. Therefore, pursuant to CAA section 112(d)(5), we 
are proposing to establish standards for new ARVs at facilities where 
EtO use is at less than 1 tpy under CAA section 112(d)(5). 
Specifically, we are proposing to require these facilities to 
continuously reduce emissions from existing ARVs by 99

[[Page 22814]]

percent. We are soliciting comment on this proposed standard for new 
ARVs at facilities where EtO use is less than 1 tpy. In addition, we 
solicit comment on several aspects of this requirement, including the 
true effectiveness of this requirement on reducing EtO emissions, any 
capital and annual costs that we did not account for, the time that is 
needed to comply with this requirement, and any other potential 
barriers to or impacts of imposing this requirement (Comment C-17). In 
addition, for the same reason discussed in section III.B.1.a of this 
preamble, we solicit comment on whether to include an alternative lb/hr 
limit that is equivalent to 99 percent emission reduction for new ARVs 
at facilities where EtO use is less than 1 tpy and whether 5.5E-6 lb/
hr, which we calculated using the method described in section 
III.B.1.a, is an appropriate alternative standard that is equivalent to 
the proposed 99 percent emission reduction standard for new ARVs at 
facilities where EtO use is less than 1 tpy (Comment C-18).
5. CEV at Facilities Where EtO Use Is at Least 10 Tpy
    On December 6, 1994 (59 FR 62585), we promulgated MACT standards 
for point sources, including CEVs, at commercial sterilization 
facilities where EtO use is at least 10 tpy. Emissions from CEVs occur 
following sterilization, as explained below. After the sterilization 
cycle in the sterilization chamber is completed and the chamber is 
vented to the SCV (i.e., after most of the EtO gas is removed and after 
the inert nitrogen (N2) washes and air washes are 
completed), the sterilized product and packaging remain in the 
sterilization chamber along with a small amount of EtO. CEVs evacuate 
EtO-laden air from the sterilization chamber after the chamber door is 
opened for product unloading following the completion of sterilization 
and associated gas washes. The CEV reduces the amount of EtO that 
workers are exposed to while those workers remove sterilized material 
from the chamber. This contributes to a facility's ability to meet U.S. 
Occupational Safety and Health Administration (OSHA) workplace exposure 
standards.\26\ Following promulgation of the original rule, the EPA 
suspended certain compliance deadlines and ultimately removed the 
standards for CEVs due to safety concerns. In the late 1990s, there 
were multiple explosions at commercial sterilization facilities that 
were initially suspected to be related to the EtO Commercial 
Sterilization NESHAP requirements. In response, the EPA suspended 
compliance with the rule for one year pending the investigation of the 
explosions (62 FR 64736, December 9, 1997). In 1998, the suspension of 
the compliance dates was extended for the ARVs and the CEVs but not for 
SCVs (63 FR 66990, December 4, 1998). It was also later determined that 
EtO emissions from aeration rooms could be safely controlled, and the 
suspensions for the ARVs NESHAP standards were not further extended 
past December 2000 (64 FR 67789, December 3, 1999). For CEVs, it was 
determined that the primary contributing issue leading to the 
explosions was that EtO concentrations were above the lower explosive 
limit (LEL) within the CEV gas streams, and the EPA extended the 
suspension of the rule requirements for CEVs. The LEL is the minimum 
concentration of a vapor in air below which propagation of a flame does 
not occur in the presence of an ignition source.\27\ An explosion risk 
occurs if the concentration of EtO exceeds the LEL. The EPA could not 
conclude, at the time, that the CEVs could be safely controlled, so the 
standards for CEVs were removed in 2001 (66 FR 55577, November 2, 
2001).
---------------------------------------------------------------------------

    \26\ 29 CFR 1910.1047.
    \27\ 29 CFR 1915.11.
---------------------------------------------------------------------------

    Following the removal of the CEV regulatory requirement, many EtO 
sterilization facilities ceased operating controls for EtO emissions 
from the CEV. The safety issues that prevented earlier control 
techniques from being applied were linked to EtO concentrations in the 
sterilization chamber that exceeded the LEL for EtO. Since the late 
1990s and early 2000s, however, facilities have begun revising their 
operating procedures related to the CEV to address the explosion issue. 
Specifically, facilities that control their CEV emissions have made 
process changes to avoid exceeding 10 to 25 percent of the LEL. Such 
process changes include (1) Reducing the EtO concentration in the 
sterilization chamber before opening the chamber door and (2) using an 
automated lock on the sterilizer chamber door. As part of these process 
changes, facilities are using additional final air washes in the 
sterilization cycle to further reduce the EtO concentration in the 
sterilization chamber prior to opening the chamber door and venting the 
CEV to the control system. In addition, the automated lock on the 
sterilization chamber door prohibits the door from opening until a non-
explosive EtO concentration level is achieved in the chamber. Today 
there are 40 facilities that have CEVs, 34 of which are controlling 
their CEV emissions. The last known explosion involving CEVs happened 
in 2004, and safety incidents involving CEVs have not occurred since. 
For these reasons, we have determined that CEVs can be safely 
controlled.
    The previous CEV standard required facilities where EtO use is at 
least 10 tpy to either (1) Combine their emissions from their CEVs 
(i.e., to manifold their emissions) and send the combined emissions to 
a control device that was used to comply with the SCV or ARV standard 
or (2) achieve 99 percent emission reduction for their CEVs. At the 
time the rule was promulgated, there were no facilities that were 
controlling their CEVs with a dedicated control device. Rather, CEVs 
were routed to a control device used to control emissions from other 
vents (59 FR 62585, 62587). Therefore, no facility was demonstrating 99 
percent emission reduction for their CEVs. Today, however, multiple 
facilities, where EtO use is at least 10 tpy, are routing CEV emissions 
to dedicated control devices and demonstrating the 99 percent emission 
reduction. There are 34 facilities where EtO use is at least 10 tpy and 
that also have CEVs, and 31 of these facilities are controlling their 
CEV emissions. Of these 31 facilities, 13 use a catalytic oxidizer, ten 
use a gas/solid reactor, three use an acid-water scrubber, three use an 
acid-water scrubber and gas/solid reactor in series, and two use a 
thermal oxidizer. There are 12 facilities that have performance and 
engineering tests available for CEVs; six of these facilities conducted 
emissions testing when one CEV was venting and most of these contained 
a single test run for each CEV unit. Of those six facilities, two are 
controlling their CEV emissions using catalytic oxidizers, two are 
using gas/solid reactors, one is using an acid-water scrubber, and one 
is using an acid-water scrubber and gas/solid reactor in series.
    Because facilities are currently routing CEVs to dedicated control 
systems and demonstrating the emission reductions achieved, we have re-
calculated the MACT floors for CEVs at facilities where EtO use is at 
least 10 tpy. We ranked the performance of the CEVs for which data are 
available. The best performing 12 percent of CEVs for which data are 
available consists of one CEV that is being controlled by a gas/solid 
reactor. We then used the upper prediction limit (UPL) approach to 
develop the MACT floor for existing sources. As mentioned in the EPA's 
Response to Remand of the Record for Commercial and Industrial Solid 
Waste Incineration Units, available at https://www.regulations.gov/
document/EPA-

[[Page 22815]]

HQ-OAR-2003-0119-2707, the UPL approach predicts the level of emissions 
that the sources upon which the floor is based are expected to meet 
over time, considering both the average emissions level achieved as 
well as emissions variability and the uncertainty that exists in the 
determination of emissions variability given the available, short-term 
data. Our practice is to use the UPL's 99th percentile, or UPL 99, as 
that is the level of emissions that we are 99 percent confident is 
achieved by the average source represented in a dataset over a long-
term period based on its previous, measured performance history as 
reflected in short term stack test data. The UPL 99 value of the 
existing source MACT floor is 3.2E-4 lb/hr. The UPL 99 EtO 
concentration that corresponds to this emission rate is 30 ppbv. Based 
on our review of available EtO measurement instruments and our 
demonstration program, we find the in-stack detection level for EtO, 
given the current technology, and potential make-up of emission 
streams, is approximately 10 ppbv. Some EtO CEMS manufacturers claim 
instrument detection levels much lower than 10 ppbv. However, we 
believe at the current time, this is the lowest level that can be 
consistently demonstrated and replicated across a wide range of 
emission profiles. We expect that EtO CEMS manufacturers, measurement 
companies, and laboratories will continue to improve EtO detection 
levels. In the meantime, consistent with our practice regarding 
reducing relative measurement imprecision by applying a multiplication 
factor of 3 to the representative detection level (RDL), the average 
detection level of the best performers, or, in this case, the better 
performing instruments, so that measurements at or above this level 
have a measurement accuracy within 10 to 20 percent- similar to that 
contained in the American Society of Mechanical Engineers (ASME) ReMAP 
study,\28\ we apply a multiplication factor of 3 to the RDL of 10 ppbv, 
which yields a workable-in-practice lower measurable value of 30 ppbv. 
For reference, below is the equation that relates the EtO 
concentration, EtO emission rate, and volumetric flow rate of the 
exhaust stream:
---------------------------------------------------------------------------

    \28\ See the discussion in the MATS rule preamble at 77 FR 9370, 
February 16, 2012.
[GRAPHIC] [TIFF OMITTED] TP13AP23.111

    Where, EtOC is the EtO concentration (in ppbv), EtOER is the EtO 
emission rate (in lb/hr), Q is the volumetric flow rate (in dry 
standard cubic feet per hour), 44.05 is the molecular weight of EtO, 
and 385.1 is the conversion factor for standard temperature and 
pressure. Since the MACT floor of 3.2E-4 lb/hr already represents 3 x 
RDL, there are no more stringent (i.e., beyond-the-floor) options to 
consider as there would be difficulty demonstrating compliance at any 
such lower limit. Therefore, the proposed standard for existing CEVs at 
facilities using at least 10 tpy EtO is 3.2E-4 lb/hr.
    For new sources, CAA section 112(d)(3) requires that the standard 
shall not be less stringent than the emission control that is achieved 
in practice by the best controlled similar source. In this case, the 
best controlled similar source is also the CEV that is being controlled 
by a gas/solid reactor and the data of which is used to determine the 
MACT floor for existing sources. Therefore, the new source MACT floor 
is equivalent to the existing source MACT floor, which is 3.2E-4 lb/hr. 
As explained above, because this emission limit represents the lowest 
level at which compliance can be demonstrated, the EPA did not consider 
more stringent (i.e., beyond-the-floor) options. Therefore, the 
proposed standard for new CEVs at facilities using at least 10 tpy EtO 
is 3.2E-4 lb/hr.
    For the reasons explained above, our proposed MACT standards under 
CAA sections 112(d)(2) and (3) for both new and existing CEVs at 
facilities where EtO use is at least 10 tpy require these facilities to 
limit the EtO emission rate from each new and existing CEV to 3.2E-4 
lb/hr. We are soliciting comment on the proposed standards (Comment C-
19).
6. CEV at Facilities Where EtO Use Is at Least 1 Tpy but Less Than 10 
Tpy
a. Existing Sources
    The current subpart O does not contain emission standards for CEVs 
at facilities where EtO use is at least 1 tpy but less than 10 tpy. In 
the December 6, 1994 (59 FR 62585) NESHAP, we promulgated a GACT 
standard that required facilities, where EtO use is at least 1 tpy but 
less than 10 tpy, to achieve a maximum chamber EtO concentration limit 
of 5,300 ppm prior to activation of the chamber exhaust. Safety issues 
discussed in section III.B.5 of this preamble led to the removal of 
this CEV standard in 2001 (66 FR 55577, November 2, 2001). As explained 
above, the safety issues appear to have been addressed through process 
changes for CEV that facilities have since implemented (i.e., reduce 
the EtO concentration in the sterilization chamber before opening the 
chamber door and use of an automated lock on the sterilizer chamber 
door). Also, as explained above, there were no dedicated controls for 
CEVs at the time the rule was promulgated. Today, however, facilities 
where EtO use is at least 1 tpy but less than 10 tpy are routing CEV 
emissions to control devices. Therefore, we are proposing emission CEV 
standards that will reflect the current status of controls.
    There are 18 facilities where EtO use is at least 1 tpy but less 
than 10 tpy, six of which have CEVs. Of these six facilities, three are 
currently controlling their CEV emissions. All of these facilities use 
catalytic oxidizers. A performance test is available for CEVs at one 
facility where EtO use is at least 1 tpy but less than 10 tpy, where 
this facility uses a gas/solid reactor. We reviewed this performance 
test, and the reported percent reduction was 99.99 percent.
    For existing sources, we considered two potential GACT options for 
reducing EtO emissions from this group: the first option reflects the 
use of emission controls on the CEVs, and the second option reflects 
applying the BMP described in section III.B.1.a, which would require 
facilities to configure their sterilization cycles and either the Cycle 
Calculation Approach or the Bioburden/Biological Indicator Approach to 
achieve sterility assurance in accordance with ISO 11135:2014 and ISO 
11138-1:2017. With respect to the first option, because 3 out of 6 
facilities (50 percent) with CEVs and EtO usage of at least 1 tpy but 
less than 10 tpy are already using controls to reduce CEV emissions, 
and we have no reason to believe that the other three cannot do the 
same, we consider emission controls

[[Page 22816]]

to be generally available for existing CEVs at these facilities. 
Evaluating the available information on controls, including the 
documented control efficiency for one unit in the category and the 
documented control efficiencies for the types of controls used on 
similar sources, the EPA determined that a control efficiency of 99 
percent is generally available for existing CEVs at facilities using at 
least 1 tpy but less than 10 tpy of EtO.
    The second potential GACT option we considered was the same 
management practice discussed in section III.B.1.a of this preamble, 
which would require facilities to follow either the Cycle Calculation 
Approach or the Bioburden/Biological Indicator Approach to achieve 
sterility assurance in accordance with ISO 11135:2014 and ISO 11138-
1:2017.
    The impacts of these two options are presented in Table 11.

  Table 11--Nationwide Emissions Reduction and Cost Impacts of Options Considered Under CAA Section 112(d)(5) for Existing CEVs at Facilities Where EtO
                                                       Use Is at Least 1 TPY but Less Than 10 TPY
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                          EtO emission         Cost
                 Option                         Proposed standard         Total capital     Total annual costs ($/yr)      reductions     effectiveness
                                                                         investment ($)                                       (tpy)        ($/ton EtO)
--------------------------------------------------------------------------------------------------------------------------------------------------------
1......................................  99 percent emission reduction.        $829,901  $245,764......................            0.11       $2,315,197
2......................................  BMP (estimated 50 percent                    0  570,000 (one-time annual cost)          5.5E-2       10,383,471
                                          emission reduction).                            \1\.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ This includes the cost for testing to verify that the new sterilization process complies with ISO 11135:2014 and ISO 11138-1:2017, as well as re-
  submitting to FDA for approval. It is expected that facilities will only incur this cost once and it is assumed to be incurred in the first year of
  compliance, but it is treated as an annual cost for the purposes of estimating total annual costs (i.e., annualized capital costs plus annual costs)
  in the analysis.

    Based on the estimates above, we find both options to be cost 
effective. While these cost-effectiveness numbers may seem high, EtO is 
a highly potent carcinogen, and the cost-effectiveness numbers of these 
options are within the range of the values that we have determined to 
be cost-effective for highly toxic HAPs. We are proposing Option 1 for 
the following reasons. First, while both options are considered 
generally available under CAA section 112(d)(5), Option 1 would achieve 
greater emission reduction than Option 2. Second, Option 1 would ensure 
that facilities that are currently reducing emissions from CEVs using 
emission controls would continue to do so, whereas Option 2 would allow 
these facilities to remove their existing controls and potentially 
increase their emissions from CEVs. Third, Option 1 would incur fewer 
annual costs than Option 2. Therefore, pursuant to CAA section 
112(d)(5), we are proposing Option 1 for existing CEVs at facilities 
where EtO use is at least 1 tpy but less than 10 tpy. Specifically, we 
are proposing to require these facilities to continuously reduce 
emissions from existing CEVs by 99 percent. We solicit comment on this 
proposed standard, including whether uncontrolled sources can use 
controls to reduce EtO emissions. In addition, we solicit comment on 
several aspects of this requirement, including the true effectiveness 
of this requirement on reducing EtO emissions, any capital and annual 
costs that we did not account for, the time that is needed to comply 
with this requirement, and any other potential barriers to or impacts 
of imposing this requirement (Comment C-20). In addition, for the same 
reason discussed in section III.B.1.a of this preamble, we solicit 
comment on whether to include an alternative lb/hr limit that is 
equivalent to 99 percent emission reduction for existing CEVs at 
facilities where EtO use is at least 1 tpy but less than 10 tpy and 
whether 1.6E-4 lb/hr, which we calculated using the method described in 
section III.B.1.a, is an appropriate alternative standard that is 
equivalent to the proposed 99 percent emission reduction standard for 
existing CEVs at facilities where EtO use is at least 1 tpy but less 
than 10 tpy (Comment C-21).
b. New Sources
    For new CEVs at facilities where EtO use is at least 1 tpy but less 
than 10 tpy, we considered two potential GACT options similar to those 
evaluated for existing CEVs at facilities where EtO use is at least 1 
tpy but less than 10 tpy, for the same reasons explained above. The 
first potential GACT option would require achieving 99 percent emission 
reduction. The second potential GACT option we considered is a BMP 
described in section III.B.1.a, which would require facilities to 
follow either the Cycle Calculation Approach or the Bioburden/
Biological Indicator Approach to achieve sterility assurance in 
accordance with ISO 11135:2014 and ISO 11138-1:2017. The impacts of 
these options, which are presented in Table 12 of this preamble, are 
based on a model plant for new CEVs at a new facility using at least 1 
tpy but less than 10 tpy EtO with the following assumptions reflecting 
the average of each of the parameters at existing facilities using at 
least 1 tpy but less than 10 tpy EtO:
     Number of CEVs: two.
     Annual EtO use: 7 tpy.
     Annual operating hours: 6,000.
     Portion of EtO going to CEVs: 1 percent.
     CEV flow rate: 20 cfs.
     Number of unique cycles: three.

Table 12--Model Plant Emissions Reduction and Cost Impacts of Options Considered Under CAA Section 112(d)(5) for New CEVs at Facilities Where EtO Use Is
                                                           at Least 1 TPY but Less Than 10 TPY
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                           EtO emission        Cost
                 Option                         Proposed standard          Total capital     Total annual costs ($/yr)      reductions     effectiveness
                                                                          investment ($)                                       (tpy)        ($/ton EtO)
--------------------------------------------------------------------------------------------------------------------------------------------------------
1......................................  99 percent emission reduction..         $92,211  $46,979.......................          6.9E-2        $677,911

[[Page 22817]]

 
2......................................  BMP (estimated 50 percent                     0  90,000 (one-time annual                 3.5E-2       2,571,429
                                          emission reduction).                             cost)\1\.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ This includes the cost for testing to verify that the new sterilization process complies with ISO 11135:2014 and ISO 11138-1:2017, as well as re-
  submitting to FDA for approval. It is expected that facilities will only incur this cost once and it is assumed to be incurred in the first year of
  compliance, but it is treated as an annual cost for the purposes of estimating total annual costs (i.e., annualized capital costs plus annual costs)
  in the analysis.

    Based on the estimates above, we find both options to be cost 
effective. While these cost-effectiveness number for Option 2 may seem 
high, EtO is a highly potent carcinogen, and the cost-effectiveness 
number of Option 2 is within the range of the values that we have 
determined to be cost-effective for highly toxic HAPs. While both 
options are considered generally available under CAA section 112(d)(5), 
Option 1 would achieve greater emission reductions and would incur 
fewer annual costs than Option 2. Therefore, pursuant to CAA section 
112(d)(5), we are proposing to establish standards for new CEVs at 
facilities where EtO use is at least 1 tpy but less than 10 tpy under 
CAA section 112(d)(5). Specifically, we are proposing to require these 
facilities to continuously reduce emissions from new CEVs by 99 
percent. We are soliciting comment on this proposed standard. In 
addition, we solicit comment on several aspects of this requirement, 
including the true effectiveness of this requirement on reducing EtO 
emissions, any capital and annual costs that we did not account for, 
the time that is needed to comply with this requirement, and any other 
potential barriers to or impacts of imposing this requirement (Comment 
C-22). In addition, for the same reason discussed in section III.B.1.a 
of this preamble, we solicit comment on whether to include an 
alternative lb/hr limit that is equivalent to 99 percent emission 
reduction for new CEVs at facilities where EtO use is at least 1 tpy 
but less than 10 tpy and whether 1.2E-4 lb/hr, which we calculated 
using the method described in section III.B.1.a, is an appropriate 
alternative standard that is equivalent to the proposed 99 percent 
emission reduction standard for new CEVs at facilities where EtO use is 
at least 1 tpy but less than 1 tpy (Comment C-23).
7. CEV at Facilities Where EtO Use Is Less Than 1 Tpy
a. Existing Sources
    The current subpart O does not contain emission standards for CEVs 
at facilities where EtO use is less than 1 tpy, nor did the EPA 
previously promulgate such standards. There are no facilities where EtO 
use is less than 1 tpy that have CEVs. It is possible, however, for a 
facility with existing CEVs to lower its EtO use to below 1 tpy as well 
as for newly constructed facilities to have CEVs with EtO usage below 1 
tpy. Therefore, we are proposing CEV standards for facilities with EtO 
usage below 1 tpy.
    For existing sources, we considered two potential GACT options for 
reducing EtO emissions from this group: the first option considers 
setting an emission standard that reflects the use of emission controls 
on the CEVs, and the second option considers applying the BMP discussed 
in section III.B.1.a of this preamble, which would require facilities 
to follow either the Cycle Calculation Approach or the Bioburden/
Biological Indicator Approach to achieve sterility assurance in 
accordance with ISO 11135:2014 and ISO 11138-1:2017. With respect to 
the first option, any existing CEV at a facility using less than 1 tpy 
EtO can only be from an existing facility that is currently using more 
than 1 tpy of EtO but in the future lowers its EtO use to below 1 tpy. 
As described in section III.B.5 of this preamble, the proposed MACT 
standards for CEVs at facilities using at least 10 tpy of EtO reflect 
the use of emission controls. We also consider emission controls to be 
generally available for CEVs at facilities where EtO use is at least 1 
tpy but less than 10 tpy, as explained in section III.B.6 of this 
preamble. We have no reason to believe that these facilities cannot 
continue to control their CEV emissions should they ever reduce their 
EtO usage to below 1 tpy. In light of the above, we consider emission 
controls to also be generally available for existing CEVs at facilities 
with EtO usage below 1 tpy. We considered a standard of 99 percent 
emission reduction, which is the same standard we are proposing for 
existing CEVs at facilities using at least 1 tpy but less than 10 tpy 
of EtO. We do not have reason to believe that a facility with existing 
CEVs cannot meet this standard upon reducing EtO use to less than 1 
tpy. The second potential GACT option we considered was the same 
management practice discussed in section III.B.1.a of this preamble, 
which would require facilities to follow either the Cycle Calculation 
Approach or the Bioburden/Biological Indicator Approach to achieve 
sterility assurance in accordance with ISO 11135:2014 and ISO 11138-
1:2017.
    We are proposing Option 1 for the following reasons.\29\ First, 
Option 1 would achieve greater emission reduction than Option 2. 
Second, Option 1 would ensure that facilities that are currently 
reducing emissions from CEVs using emission controls would continue to 
do so upon lowering EtO use, whereas Option 2 would allow these 
facilities to remove their existing controls and potentially increase 
their emissions from CEVs. Therefore, pursuant to CAA section 
112(d)(5), we are proposing Option 1 for existing CEVs at facilities 
where EtO use is less than 1 tpy. Specifically, we are proposing to 
require these facilities to continuously reduce emissions from existing 
CEVs by 99 percent. We solicit comment on this proposed standard. In 
addition, we solicit comment on several aspects of this requirement, 
including the true effectiveness of this requirement on reducing EtO 
emissions, any capital and annual costs that we did not account for, 
the time that is needed to comply with this requirement, and any other 
potential barriers to or impacts of imposing this requirement (Comment 
C-24). In addition, for the same reason discussed in section

[[Page 22818]]

III.B.1.a of this preamble, we solicit comment on whether to include an 
alternative lb/hr limit that is equivalent to 99 percent emission 
reduction for existing CEVs at facilities where EtO use is less than 1 
tpy and whether 1.6E-4 lb/hr, which we calculated using the method 
described in section III.B.1.a, is an appropriate alternative standard 
that is equivalent to the proposed 99 percent emission reduction 
standard for existing CEVs at facilities where EtO use is less than 1 
tpy (Comment C-25).
---------------------------------------------------------------------------

    \29\ Unlike the other section III subsections in this preamble, 
which present costs impacts of the options being considered in a 
table format, we cannot do the same here because there are no 
existing CEVs at facilities using less than 1 tpy of EtO.
---------------------------------------------------------------------------

b. New Sources
    For new CEVs at facilities where EtO use is less than 1 tpy, we 
considered two potential GACT options similar to those evaluated for 
existing CEVs at facilities where EtO use is less than 1 tpy for the 
same reasons explained above. The first potential GACT option would 
require achieving 99 percent emission reduction. These assumptions are 
as follows:
     Number of CEVs: two.
     Annual EtO use: 0.99 tpy.
     Annual operating hours: 6,000.
     Portion of EtO going to CEVs: 1 percent.
     CEV flow rate: 12 cfs.
     Number of unique cycles: three.
    The second potential GACT option we considered is the BMP described 
in section III.B.1.a, which would require facilities to follow either 
the Cycle Calculation Approach or the Bioburden/Biological Indicator 
Approach to achieve sterility assurance in accordance with ISO 
11135:2014 and ISO 11138-1:2017. The impacts of these two options are 
presented in Table 13 of this preamble:

Table 13--Model Plant Emissions Reduction and Cost Impacts of Options Considered Under CAA Section 112(d)(5) for New CEVs at Facilities Where EtO Use Is
                                                                     Less Than 1 TPY
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                           EtO emission        Cost
                 Option                         Proposed standard          Total capital     Total annual costs ($/yr)      reductions     effectiveness
                                                                          investment ($)                                       (tpy)        ($/ton EtO)
--------------------------------------------------------------------------------------------------------------------------------------------------------
1......................................  99 percent emission reduction..         $92,211  $41,502.......................          9.5E-3      $4,350,265
2......................................  BMP (estimated 50 percent                     0  90,000 (one-time annual cost)           5.0E-3      18,181,818
                                          emission reduction).                             \1\.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ This includes the cost for testing to verify that the new sterilization process complies with ISO 11135:2014 and ISO 11138-1:2017, as well as re-
  submitting to FDA for approval. It is expected that facilities will only incur this cost once and it is assumed to be incurred in the first year of
  compliance, but it is treated as an annual cost for the purposes of estimating total annual costs (i.e., annualized capital costs plus annual costs)
  in the analysis.

    Based on the estimates above, we find both options to be cost 
effective. While these cost-effectiveness numbers may seem high, EtO is 
a highly potent carcinogen, and the cost-effectiveness numbers of these 
options are within the range of the values that we have determined to 
be cost-effective for highly toxic HAPs. While both options are 
considered generally available under CAA section 112(d)(5), Option 1 
would achieve greater emission reductions and would incur fewer annual 
costs than Option 2. Therefore, pursuant to CAA section 112(d)(5), we 
are proposing to establish standards for new CEVs at facilities where 
EtO use is at less than 1 tpy under CAA section 112(d)(5). 
Specifically, we are proposing to require these facilities to 
continuously reduce emissions from new CEVs by 99 percent. We are 
soliciting comment on this proposed standard. In addition, we solicit 
comment on several aspects of this requirement, including the true 
effectiveness of this requirement on reducing EtO emissions, any 
capital and annual costs that we did not account for, the time that is 
needed to comply with this requirement, and any other potential 
barriers to or impacts of imposing this requirement (Comment C-26). In 
addition, for the same reason discussed in section III.B.1.a of this 
preamble, we solicit comment on whether to include an alternative lb/hr 
limit that is equivalent to 99 percent emission reduction for new CEVs 
at facilities where EtO use is less than 1 tpy and whether 1.2E-4 lb/
hr, which we calculated using the method described in section 
III.B.1.a, is an appropriate alternative standard that is equivalent to 
the proposed 99 percent emission reduction standard for new CEVs at 
facilities where EtO use is less than 1 tpy (Comment C-27).
8. Room Air Emission Sources
    The current subpart O does not regulate room air emissions. In the 
Commercial Sterilization Facilities source category, facilities tend to 
group room air emission sources together to capture and route their 
emissions to a common control device, rather than to control each room 
air emission source individually. While multiple room air emission 
sources at a facility are often routed to the same control system, 
sometimes room air emission sources are routed to different control 
systems, and the configurations vary from facility to facility. The 
configurations of room air emission sources are the following: all room 
air emission sources routed together; PoAHSM routed together, and all 
other room air emission sources routed together; and all point and room 
air emission sources routed together. In defining affected sources of 
room air emission sources for purposes of setting standards under CAA 
section 112, the EPA grouped room air emission sources based on process 
activities that occur prior to aeration and those process activities 
that occur after aeration of materials. This approach reflects the most 
common emission control configuration, which is to capture and route 
PoAHSM emissions to one control system and to capture and route all 
other room air emission sources to another control system. While room 
air emission sources overall tend to have higher flow rates and lower 
EtO concentrations compared to point sources at EtO commercial 
sterilization facilities, the EtO concentration and flow rate 
characteristics of emission streams can differ for streams prior to and 
after aeration. The difference in flow rates that occur for the pre- 
and post-aeration room air sources is important, as the post-aeration 
handling of sterilized material room areas (e.g., quarantine, shipping, 
and warehouse areas) have the largest floor area and room volumes at 
the facility and also have the largest flow rates of any of the room 
air emission sources. We grouped room air emission sources into two 
groups. Group 1 room air emission sources include indoor EtO storage, 
EtO dispensing, vacuum pump operation, and pre-aeration handling of 
sterilized materials. Group 2 room air emission sources include post-
aeration handling of sterilized material.
a. Existing Group 1 Room Air Emissions at Major Source Facilities
    There are 47 facilities that use at least 10 tpy of EtO and have 
Group 1 room

[[Page 22819]]

air emissions. Based on our review of available state and local 
permits, as well as emissions data, we believe that all of these 
facilities are synthetic area sources. Of these, 24 facilities are 
controlling all their Group 1 emissions, while 2 are partially 
controlling their Group 1 room air emissions. Of the 24 facilities that 
are controlling all their Group 1 room air emissions, 17 use gas/solid 
reactors, eight use catalytic oxidizers, and five use acid-water 
scrubbers. Note that this does not sum to 26 because some facilities 
use different types of control systems for reducing Group 1 room air 
emissions. Of the two facilities that partially control their Group 1 
room air emissions, both use gas/solid reactors.
    We have calculated the MACT floor for existing Group 1 room air 
emissions at major source facilities. CAA section 112(d)(3)(A) requires 
that the MACT floor be based on the best performing 12 percent of 
existing sources for which data are available. We ranked the 
performance of the facilities with Group 1 room air emissions for which 
data are available. There are only three performance tests that are 
currently available, so the best performing 12 percent of exiting 
sources for which data are available consists of Group 1 room air 
emissions at one facility that is controlling such emissions with a 
gas/solid reactor. That facility reported an emission rate of 4.8E-4 
lb/hr. We then used the UPL to develop the MACT floor for existing 
sources. The UPL 99 value of the existing source MACT floor is 7.7E-4 
lb/hr. The EtO concentration (UPL 99 value) that corresponds to this 
emission rate is 20 ppbv. Since this is below 3 x RDL, we adjusted the 
MACT floor by determining the emission rate using 30 ppbv and the 
average volumetric flow rate of the Group 1 room air emissions stream 
at the facility, which is 6,202 dry standard cubic feet per minute 
(dscfm). This results in an adjusted MACT floor of 1.3E-3 lb/hr. Since 
this represents 3 x RDL, there are no more stringent (i.e., beyond-the-
floor) options to consider as there would be difficulty demonstrating 
compliance with a limit below 3 x RDL. Therefore, the proposed MACT 
standard for existing Group 1 room air emissions at major source 
facilities is 1.3E-3 lb/hr.
    The proposed standards are based on complete capture of the 
emission from Group 1 room air emissions, which are then routed to an 
APCD. In recent years, state and local agencies have required EtO 
commercial sterilization facilities to capture room air emissions and 
route the emissions to an APCD. EtO commercial sterilization facilities 
in Illinois, Georgia, California, North Carolina, and other states have 
installed PTEs and add-on control systems to reduce releases of room 
air emissions. At most of these facilities, the PTEs meet the 
requirements of EPA Method 204,\30\ and the enclosure is monitored 
continuously to demonstrate capture efficiency. EPA Method 204 (40 CFR 
part 51, appendix M) was promulgated on June 16, 1997 (62 FR 32500), as 
part of a suite of methods to support State Implementation Plans for 
ozone for determining capture efficiency, for the purpose of reducing 
volatile organic compounds. Since this time, EPA Method 204 has been 
incorporated into a number of NESHAP (e.g., Surface Coating NESHAPs) 
for demonstrating compliance with PTE standards. EPA Method 204 
provides the design criteria for PTEs, including (1) Criteria for the 
proximity of the emitting points to the natural draft openings (NDOs), 
(2) location of the exhaust hoods, (3) total area of all NDOs, (4) 
average facial velocity through the NDOs, (5) and requirements for 
access doors and windows that are not considered NDOs, to be closed. 
When all these criteria are met and verified, an affected source can 
assume 100 percent capture. Additionally, EPA Method 204 includes 
requirements to route the captured and contained EtO-laden gas for 
delivery to a control system. EPA Method 204 does not include 
procedures for demonstrating continuous compliance, however these 
procedures and associated standards may be defined in the affected rule 
and/or state permit condition. An example of this requirement can be 
found in 40 CFR 63.5725(f) of the NESHAP for Boat Manufacturing (40 CFR 
part 63, subpart VVVV), where we require either collection of the 
facial velocity of air through all NDOs or the pressure drop across the 
enclosure. The Boat Manufacturing NESHAP also requires data on facial 
velocity and/or pressure drop at 3-hour block averages consistent with 
the requirements in Method 204. It also requires maintaining the 
direction of air flow into the enclosure at all times. These continuous 
compliance requirements are also consistent with what has been applied 
to many of the commercial sterilizers that have installed PTEs, through 
permit conditions. We are therefore proposing, as a compliance 
assurance measure, that each major source facility operate all areas 
with sources of Group 1 room air emissions in accordance with the PTE 
requirements of Method 204 of appendix M to 40 CFR part 51. We solicit 
comment on these proposed standards (Comment C-28).
---------------------------------------------------------------------------

    \30\ 40 CFR part 51, appendix M, EPA Method 204--Criteria and 
Verification of a Permanent or Temporary Total Enclosure. U.S. EPA.
---------------------------------------------------------------------------

b. New Group 1 Room Air Emissions at Major Source Facilities
    For new sources, CAA section 112(d)(3) requires that the standard 
shall not be less stringent than the emission control that is achieved 
in practice by the best controlled similar source. In this case, the 
best controlled similar source is also the Group 1 room air emissions 
that are being controlled by a gas/solid reactor and the data of which 
is used to determine the MACT floor for existing sources. Therefore, 
the new source MACT floor is equivalent to the existing source MACT 
floor, which is 1.3E-3 lb/hr. As explained above, because this emission 
limit represents the lowest level at which compliance can be 
demonstrated, the EPA did not consider more stringent (i.e., beyond-
the-floor) options. Therefore, the proposed standard for new Group 1 
room air emissions at major source facilities is 1.3E-3 lb/hr.
    For the reasons explained above, our proposed MACT standards under 
CAA sections 112(d)(2) and (3) for Group 1 room air emissions at major 
source facilities are to require these facilities to limit the Group 1 
room air EtO emission rate to 1.3E-3 lb/hr. Also, for the reasons 
explained in section III.B.8.a, to ensure complete capture of EtO 
emissions from this source and, in turn, compliance with the proposed 
standard, we are proposing to require each facility within this group 
to operate areas with Group 1 room air emissions in accordance with the 
PTE requirements of EPA Method 204 of appendix M to 40 CFR part 51. We 
solicit comment on these proposed standards (Comment C-29).
c. Existing Group 1 Room Air Emissions at Area Source Facilities
    A description of existing Group 1 room air emissions at synthetic 
area source facilities is available in section III.B.8.a of this 
preamble. Of these, 24 facilities are controlling all of their Group 1 
room air emissions. In addition, there are 38 area source facilities 
where EtO use is less than 10 tpy, 27 of which have Group 1 room air 
emissions. Of these, three facilities are controlling all their Group 1 
emissions, while three are partially controlling its Group 1 room air 
emissions. Of the three facilities that are controlling all of their 
Group 1 room air emissions, two use catalytic oxidizers, and one uses a 
gas/solid reactor and catalytic oxidizer in series. Of the three 
facilities that partially control their Group 1 room air

[[Page 22820]]

emissions, two use gas/solid reactors, one uses catalytic oxidizer, and 
one uses a wet scrubber and gas/solid reactor in series. Note that this 
does not sum to three because one facility uses different types of 
control systems for reducing Group 1 room air emissions Performance 
tests are available for Group 1 room air emissions at three synthetic 
area source facilities, all of which use gas/solid reactors. We 
reviewed these performance tests, and the reported emission rates 
ranged from 2.0E-5 lb/hr to 4.8E-4 lb/hr.\31\ As explained above in 
section III.B.8.a, the proposed MACT standard for existing Group 1 room 
air emissions at major source facilities was based on the performance 
test of one of these three facilities as that was the only facility 
within ``the best performing 12 percent of the existing sources (for 
which the Administrator has emission information)'' (CAA section 
112(d)(3)(A)). That facility reported an emission rate of 4.8E-4 lb/hr.
---------------------------------------------------------------------------

    \31\ Two of these performance tests consist of one run each, and 
the other consists of three runs. Performance tests that consist of 
only one run tend to be less reliable than those with multiple runs 
because single run tests do not provide any information about source 
variability. The emission rate for the three-run test shows the 
reported rate that has not undergone a UPL or 3 x RDL adjustment.
---------------------------------------------------------------------------

    For existing Group 1 room air emissions at area source facilities, 
we considered two potential GACT options for reducing EtO emissions 
from this group: the first option reflects the use of emission controls 
on Group 1 room air emissions, and the second option reflects applying 
a BMP to reduce EtO use per sterilization cycle (i.e., pollution 
prevention). With respect to the first option, 32 out of 74 area source 
facilities with Group 1 room air emissions are already using controls 
to reduce those emissions. We considered a standard of 1.3E-3 lb/hr, 
which is the MACT standard for Group 1 room air emissions at major 
source facilities. We find this standard to be reasonable for existing 
Group 1 room air emissions at area source facilities because it is 
within an order of magnitude of the Group 1 room air emission 
reductions shown in the 3-run performance test for an area source 
facility (4.8E-4 lb/hr). The second potential GACT option we considered 
was the same management practice discussed in section III.B.1.a, which 
would require facilities to follow either the Cycle Calculation 
Approach or the Bioburden/Biological Indicator Approach to achieve 
sterility assurance in accordance with ISO 11135:2014 and ISO 11138-
1:2017. During the sterilization process, EtO becomes trapped within 
the material and continues to off-gas after the sterilization process 
is complete. Therefore, if less EtO is used during the sterilization 
process, this can lead to a reduction in post-sterilization EtO 
emissions, including those from pre-aeration handling of sterilized 
material. In addition, a reduction in EtO use can result in less EtO 
needing to be stored at the facility, as well as less EtO throughput in 
dispensing equipment and vacuum pumps. This would, in turn, lead to a 
reduction in EtO emissions.
    The impacts of these options are presented in Table 14.

 Table 14--Nationwide Emissions Reduction and Cost Impacts of Options Considered Under CAA Section 112(d)(5) for Existing Group 1 Room Air Emissions at
                                                                 Area Source Facilities
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                           EtO emission        Cost
                 Option                       Emission rate  (lb/hr)       Total capital     Total annual costs ($/yr)      reductions     effectiveness
                                                                          investment ($)                                       (tpy)        ($/ton EtO)
--------------------------------------------------------------------------------------------------------------------------------------------------------
1......................................  1.3E-3.........................    $100,437,729  $14,719,405...................             5.4      $2,733,571
2......................................  BMP (estimated 50 percent                     0  12,570,000\1\ (one-time annual             2.8       4,445,789
                                          reduction).                                      cost.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ This includes the cost for testing to verify that the new sterilization process complies with ISO 11135:2014 and ISO 11138-1:2017, as well as re-
  submitting to FDA for approval. It is expected that facilities will only incur this cost once and it is assumed to be incurred in the first year of
  compliance, but it is treated as an annual cost for the purposes of estimating total annual costs (i.e., annualized capital costs plus annual costs)
  in the analysis.

    Based on the estimates above, we find both options to be cost 
effective. While these cost-effectiveness numbers may seem high, EtO is 
a highly potent carcinogen, and the cost-effectiveness numbers of these 
options are within the range of the values that we have determined to 
be cost-effective for highly toxic HAPs. We are proposing Option 1 for 
the following reasons. First, while both options are considered 
generally available under CAA section 112(d)(5), Option 1 would achieve 
greater emission reduction than Option 2. Second, Option 1 would ensure 
that facilities that are currently reducing emissions from Group 1 room 
air emissions using emission controls would continue to do so, whereas 
Option 2 would allow these facilities to remove their existing controls 
and potentially increase their emissions from Group 1 room air 
emissions. Therefore, pursuant to CAA section 112(d)(5), we are 
proposing Option 1 for existing Group 1 room air emissions at area 
source facilities. Specifically, we are proposing to require these 
facilities to limit the Group 1 EtO emission rate to 1.3E-3 lb/hr. 
Also, for the reasons explained in section III.B.8.a, to ensure 
complete capture of EtO emissions from this source and, in turn, 
compliance with the proposed standard, we are proposing to require each 
facility within this group to operate areas with Group 1 room air 
emissions in accordance with the PTE requirements of EPA Method 204 of 
appendix M to 40 CFR part 51. We solicit comment on these proposed 
standards. In addition, we solicit comment on several aspects of this 
requirement, including the true effectiveness of this requirement on 
reducing EtO emissions, any capital and annual costs that we did not 
account for, the time that is needed to comply with this requirement, 
and any other potential barriers to or impacts of imposing this 
requirement (Comment C-30).
d. New Group 1 Room air Emissions at Area Source Facilities.
    For new Group 1 room air emissions at area sources facilities, we 
considered the same two potential GACT options as those evaluated for 
existing Group 1 room air emissions at area source facilities for the 
same reasons explained above. The first potential GACT option (Option 
1) would require achieving an emission rate of 1.3E-3 lb/hr. The second 
potential GACT option we considered (Option 2) is a BMP that would 
require facilities to follow either the Cycle Calculation Approach or 
the Bioburden/Biological Indicator Approach to achieve sterility 
assurance in accordance with ISO 11135:2014 and ISO 11138-1:2017. The 
impacts of these options, which are presented in Table

[[Page 22821]]

15 of this preamble, are based on a model plant for new Group 1 room 
air emissions at an area source facility with the following assumptions 
reflecting the average of each of the parameters at area source 
facilities with new Group 1 room air emissions:
     EtO use: 90 tpy.
     Annual operating hours: 8,000.
     Portion of EtO going to Group 1 room air emissions: 0.4 
percent.
     Group 1 room air emissions flow rate: 300 cfs.
     Number of unique cycles: six.

 Table 15--Model Plant Emissions Reduction and Cost Impacts of Options Considered Under CAA Section 112(d)(5) for New Group 1 Room Air Emissions at Area
                                                                    Source Facilities
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                           EtO emission        Cost
                 Option                  Emission standard rate  (lb/hr)   Total capital    Total annual costs  ($/yr)      reductions     effectiveness
                                                                          investment ($)                                       (tpy)        ($/ton EtO)
--------------------------------------------------------------------------------------------------------------------------------------------------------
1......................................  1.3E-3.........................      $1,106,534  $223,464......................            0.35        $629,830
2......................................  BMP (estimated 50 percent                     0  180,000 \1\ (one-time annual              0.18       1,000,000
                                          emission reduction).                             cost).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ This includes the cost for testing to verify that the new sterilization process complies with ISO 11135:2014 and ISO 11138-1:2017, as well as re-
  submitting to FDA for approval. It is expected that facilities will only incur this cost once and it is assumed to be incurred in the first year of
  compliance, but it is treated as an annual cost for the purposes of estimating total annual costs (i.e., annualized capital costs plus annual costs)
  in the analysis.

    Based on the estimates above, we find both options to be cost 
effective. While both options are considered generally available under 
CAA section 112(d)(5), Option 1 would achieve greater emission 
reductions than Option 2. Therefore, pursuant to CAA section 112(d)(5), 
we are proposing to establish standards for new Group 1 room air 
emissions at area source facilities. Specifically, we are proposing to 
require these facilities to limit the Group 1 room air EtO emission 
rate to 1.3E-3 lb/hr. Also, as explained in section III.B.8.a, to 
ensure complete capture of EtO emissions from this source and, in turn, 
compliance with the proposed standard, we are proposing to require each 
facility within this group to operate areas with Group 1 room air 
emissions in accordance with the PTE requirements of Method 204 of 
appendix M to 40 CFR part 51. We are soliciting comment on this 
proposed standard (Comment C-31).
e. Existing Group 2 Room Air Emissions at Major Source Facilities
    There are 47 facilities where EtO use is at least 10 tpy of EtO, 
all of which are both subject to subpart O and have Group 2 room air 
emissions. Based on our review of available state and local permits, as 
well as emissions data, we believe that all these facilities are 
synthetic area sources. 24 of these facilities are controlling all 
their Group 2 room air emissions, and one facility is partially 
controlling its Group 2 room air emission. Of these 24 facilities, 20 
use gas/solid reactors, two use catalytic oxidizers, one uses acid-
water scrubbers, and one uses a catalytic oxidizer and thermal oxidizer 
in series. The one facility that is partially controlling its room air 
emissions uses a gas/solid reactor.
    We have calculated the MACT floor for existing Group 2 room air 
emissions at major source facilities. We ranked the performance of the 
facilities with Group 2 room air emissions for which data are 
available. There are only three performance tests that are currently 
available, so the best performing 12 percent of facilities for which 
data are available consists of one facility that is controlling its 
Group 2 room air emissions with a gas/solid reactor. That facility 
reported an emission rate of 8.3E-4 lb/hr. We then used the UPL to 
develop the MACT floor for existing sources. The UPL 99 value of the 
existing source MACT floor is 9.5E-4 lb/hr. The EtO concentration (UPL 
99 value) that corresponds to this emission rate is 10 ppbv. Since this 
is below 3 x RDL, we adjusted the MACT floor by determining the 
emission rate using 30 ppbv and the average flow rate of the Group 2 
room air emissions stream at the facility, which is 13,711 dscfm. This 
results in an adjusted MACT floor of 2.8E-3 lb/hr. Since this 
represents 3 x RDL, there are no more stringent (i.e., beyond-the-
floor) options to consider as there would be difficulty demonstrating 
compliance at any such lower limit. Therefore, the proposed standard 
for existing Group 2 room air emissions at major source facilities is 
2.8E-3 lb/hr.
    For the reasons explained above, our proposed MACT standards under 
CAA sections 112(d)(2) and (3) for existing Group 2 room air emissions 
at major source facilities are to require these facilities to limit the 
Group 2 room air EtO emission rate to 2.8E-3 lb/hr.\32\ Also, for the 
reasons explained in section III.B.8.a, to ensure complete capture of 
EtO emissions from this source and, in turn, compliance with the 
proposed standard, we are proposing to require each facility within 
this group to operate areas with Group 2 room air emissions in 
accordance with the PTE requirements of Method 204 of appendix M to 40 
CFR part 51. We solicit comment on these proposed standards (Comment C-
32).
---------------------------------------------------------------------------

    \32\ While data from synthetic area sources are included with 
data from major sources in determining the MACT floor as described 
above, synthetic area sources, which limit their potential to emit 
HAP below the major source threshold, are not major sources and 
therefore not subject to major source standards under section 112.
---------------------------------------------------------------------------

f. New Group 2 Room Air Emissions at Major Source Facilities
    For new sources, CAA section 112(d)(3) requires that the standard 
shall not be less stringent than the emission control that is achieved 
in practice by the best controlled similar source. In this case, the 
best controlled similar source is also the Group 2 room air emissions 
that are being controlled by a gas/solid reactor and the data of which 
is used to determine the MACT floor for existing sources. Therefore, 
the new source MACT floor is equivalent to the existing source MACT 
floor, which is 2.8E-3 lb/hr. As explained above, because this emission 
limit represents the lowest level at which compliance can be 
demonstrated, the EPA did not consider more stringent (i.e., beyond-
the-floor) options. Therefore, the proposed standard for new Group 2 
room air emissions at major source facilities is 2.8E-3 lb/hr.
    For the reasons explained above, our proposed MACT standards under 
CAA sections 112(d)(2) and (3) for new Group 2 room air emissions at 
major source facilities are to require these facilities to limit the 
Group 2 room air EtO emission rate to 2.8E-3 lb/hr. as Also, as 
explained in III.B.8.a, to ensure complete capture of EtO emissions 
from this source and, in turn, compliance with the proposed standard, 
we are

[[Page 22822]]

proposing to require each facility within this group to operate areas 
with Group 2 room air emissions in accordance with the PTE requirements 
of EPA Method 204 of appendix M to 40 CFR part 51. We solicit comment 
on these proposed standards (Comment C-33).
g. Existing Group 2 Room Air Emissions at Area Source Facilities
    A description of synthetic area sources with existing Group 2 room 
air emissions is available in section III.B.8.c of this preamble. Of 
these, 25 facilities are controlling all of their Group 1 room air 
emissions. In addition, there are 37 facilities where EtO use is less 
than 10 tpy that are not major sources, all of which have Group 2 room 
air emissions. Two of these facilities are controlling all their Group 
2 room air emissions, while one is partially controlling its Group 2 
room air emissions. Of the 2 facilities that are controlling all of 
their Group 2 room air emissions, one uses a catalytic oxidizer, and 
one uses a gas/solid reactor. The one facility that partially controls 
its Group 2 room air emissions uses both a wet scrubber and gas/solid 
reactor in series, as well as a stand-alone gas/solid reactor. 
Performance tests are available for Group 2 room air emissions at three 
synthetic area source facilities, all of which use gas/solid reactors. 
We reviewed these performance tests, and the reported emission rates 
ranged from 5.0E-5 lb/hr to 1.8E-2 lb/hr.\33\ As explained above in 
section III.B.8.e, the proposed MACT standard for existing Group 2 room 
air emissions at major source facilities was based on the performance 
test of one of these three facilities as that was the only facility 
within ``the best performing 12 percent of the existing sources (for 
which the Administrator has emission information'' (CAA section 
112(d)(3)(A)). That facility reported an emission rate of 8.3E-4 lb/hr.
---------------------------------------------------------------------------

    \33\ Two of these performance tests consist of one run each, and 
the other consists of three runs. Performance tests that consist of 
only one run tend to be less reliable than those with multiple runs 
because single run tests do not provide any information about source 
variability. The emission rate for the three-run test shows the 
reported rate that has not undergone a UPL or 3 x RDL adjustment.
---------------------------------------------------------------------------

    For existing sources, we considered two potential GACT options for 
reducing EtO emissions from this group: the first option considers 
setting an emission standard that reflects the use of emission controls 
on Group 2 room air emissions, and the second option that reflects 
applying a BMP to reduce EtO use per sterilization cycle (i.e., 
pollution prevention). With respect to the first option, 28 out of 84 
area source facilities subject to subpart O are using controls to 
reduce Group 2 room air emissions. We considered a standard of 2.8E-3 
lb/hr (Option 1), which is the MACT standard for Group 2 room air 
emissions at major source facilities; as discussed above, the 
performance test that was used to generate the MACT floor was conducted 
at a synthetic area source facility This limit is within an order of 
magnitude of the Group 2 room air emission reductions shown in the 3-
run performance test for an area source facility (8.3E-4 lb/hr). The 
second potential GACT option we considered (Option 2) was the same 
management practice discussed in section III.B.1.a, which would require 
facilities to follow either the Cycle Calculation Approach or the 
Bioburden/Biological Indicator Approach to achieve sterility assurance 
in accordance with ISO 11135:2014. During the sterilization process, 
EtO becomes trapped within the material and continues to off-gas after 
the sterilization process is complete. Therefore, if less EtO is used 
during the sterilization process, this can lead to a reduction in post-
sterilization EtO emissions, including Group 2 room air emissions.
    The impacts of these options are presented in Table 16.

 Table 16--Nationwide Emissions Reduction and Cost Impacts of Options Considered Under CAA Section 112(d)(5) for Existing Group 2 Room Air Emissions at
                                                                 Area Source Facilities
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                           Total capital                   EtO emission        Cost
                     Option                          Emission standard rate  (lb/hr)        investment     Total annual     reductions     effectiveness
                                                                                                ($)        costs  ($/yr)       (tpy)        ($/ton EtO)
--------------------------------------------------------------------------------------------------------------------------------------------------------
1..............................................  2.8E-3.................................    $210,007,878     $27,719,141             1.4     $19,420,188
2..............................................  BMP....................................               0  \1\ 13,050,000            0.78      16,790,792
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ This includes the cost for testing to verify that the new sterilization process complies with ISO 11135:2014 and ISO 11138-1:2017, as well as re-
  submitting to FDA for approval. It is expected that facilities will only incur this cost once and it is assumed to be incurred in the first year of
  compliance, but it is treated as an annual cost for the purposes of estimating total annual costs (i.e., annualized capital costs plus annual costs)
  in the analysis.

    Based on the estimates above, we find both options to be cost 
effective. While these cost-effectiveness numbers may seem high, EtO is 
a highly potent carcinogen, and the cost-effectiveness numbers of these 
options are within the range of the values that we have determined to 
be cost-effective for highly toxic HAPs. There are multiple factors we 
consider in assessing the cost of the emission reductions. See NRDC v. 
EPA, 749 F.3d 1055, 1060 (DC Cir. April 18, 2014) (``Section 112 does 
not command EPA to use a particular form of cost analysis.''). These 
factors include, but are not limited to, total capital costs, total 
annual costs, cost-effectiveness, and annual costs compared to total 
revenue (i.e., costs to sales ratios). Our established methodology for 
assessing economic impacts of regulations indicates that the potential 
for adverse economic impacts begins when the cost to sales ratio 
exceeds five percent. According to our estimates, the annual cost of 
the emission control option for most of the affected sources discussed 
above is well below five percent.\34\ However, reducing existing Group 
2 room air emissions at area source facilities using emission control 
devices (Option 1), would significantly impact several companies 
operating nine area source facilities with Group 2 room air emissions. 
We estimate that the annual cost of controls at the level under Option 
1 would exceed five percent of revenue for these companies. Based on 
the available economic information, assuming market conditions remain 
approximately the same, we are concerned that these companies would not 
be able to sustain the costs associated with Option 1. In addition, EPA 
is aware of other facilities that, according to FDA, could impact the 
availability of certain medical devices, including those that are (1)

[[Page 22823]]

Experiencing or at risk of experiencing a shortage, (2) in high demand 
as a result of the COVID-19 pandemic, (3) used in pediatric services, 
and/or (4) sterilized exclusively at a particular facility. Therefore, 
pursuant to CAA section 112(d)(5), we are proposing Option 2 for 
existing Group 2 room air emissions at area source facilities. 
Specifically, we are proposing to require these facilities follow 
either the Cycle Calculation Approach or the Bioburden/Biological 
Indicator Approach to achieve sterility assurance in accordance with 
ISO 11135:2014 and ISO 11138-1:2017. We solicit comment on these 
proposed standards. In addition, we solicit comment on several aspects 
of this requirement, including the true effectiveness of this 
requirement on reducing EtO emissions, any capital and annual costs 
that we did not account for, the time that is needed to comply with 
this requirement, and any other potential barriers to or impacts of 
imposing this requirement (Comment C-34).
---------------------------------------------------------------------------

    \34\ See memorandum, Technical Support Document for Proposed 
Rule--Industry Profile, Review of Unregulated Emissions, CAA Section 
112(d)(6) Technology Review, and CAA Section 112(f) Risk Assessment 
for the Ethylene Oxide Emissions Standards for Sterilization 
Facilities NESHAP, located at Docket ID No. EPA-HQ-OAR-2019-0178.
---------------------------------------------------------------------------

h. New Group 2 Room Air Emissions at Area Source Facilities
    For new Group 2 room air emissions at area sources facilities, we 
considered the same two potential GACT options as those evaluated for 
existing Group 2 room air emissions at area source facilities for the 
same reasons explained above. The first potential GACT option we 
considered (Option 1) would require achieving an emission rate of 2.8E-
3 lb/hr. The second potential GACT option we considered (Option 2) is a 
BMP that would require facilities to follow either the Cycle 
Calculation Approach or the Bioburden/Biological Indicator Approach to 
achieve sterility assurance in accordance with ISO 11135:2014 and ISO 
11138-1:2017. The impacts of these options, which are presented in 
Table 17 of this preamble, are based on a model plant for new Group 2 
room air emissions at an area source facility with the following 
assumptions reflecting the average of each of the parameters at area 
source facilities:
     EtO use: 80 tpy.
     Annual operating hours: 7,000.
     Portion of EtO going to Group 2 room air emissions: 0.2 
percent.
     Group 2 room air emissions flow rate: 800 cfs.
     Number of unique cycles: five.

 Table 17--Model Plant Emissions Reduction and Cost Impacts of Options Considered Under CAA Section 112(d)(5) for New Group 2 Room Air Emissions at Area
                                                                    Source Facilities
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                           Total capital                                   EtO emission        Cost
                 Option                  Emission standard rate  (lb/hr)    investment      Total annual costs  ($/yr)      reductions     effectiveness
                                                                                ($)                                            (tpy)        ($/ton EtO)
--------------------------------------------------------------------------------------------------------------------------------------------------------
1......................................  2.8E-3.........................      $2,120,857  $378,546......................          4.3E-2      $8,820,981
2......................................  BMP (estimated 50 percent                     0  150,000 \1\ (one-time annual            2.3E-2       6,562,500
                                          emission reduction).                             cost).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ This includes the cost for testing to verify that the new sterilization process complies with ISO 11135:2014 and ISO 11138-1:2017, as well as re-
  submitting to FDA for approval. It is expected that facilities will only incur this cost once and it is assumed to be incurred in the first year of
  compliance, but it is treated as an annual cost for the purposes of estimating total annual costs (i.e., annualized capital costs plus annual costs)
  in the analysis.

    Based on the estimates above, we find both options to be cost 
effective. While these cost-effectiveness numbers may seem high, EtO is 
a highly potent carcinogen, and the cost-effectiveness numbers of these 
options are within the range of the values that we have determined to 
be cost-effective for highly toxic HAPs. We are proposing Option 1 for 
the following reasons. While both options are considered generally 
available under CAA section 112(d)(5), Option 1 would achieve greater 
emission reductions than Option 2. Also, unlike Option 1 for existing 
Group 2 room air emissions at area source facilities, companies 
constructing new source(s) of Group 2 room air emissions in the future 
can plan and design operations to avoid significant impact (or choose 
not to build). Therefore, pursuant to CAA section 112(d)(5), we are 
proposing to establish standards for new Group 2 room air emissions at 
area source facilities. Specifically, we are proposing to require these 
facilities to limit the Group 2 room air EtO emission rate to 2.8E-3 
lb/hr. As explained in section III.B.8.a of this preamble, to ensure 
complete capture of EtO emissions from this source and, in turn, 
compliance with the proposed standard, we are proposing to require each 
facility within this group to operate areas with Group 2 room air 
emissions in accordance with the PTE requirements of EPA Method 204 of 
appendix M to 40 CFR part 51. We are soliciting comment on this 
proposed standard. In addition, we solicit comment on several aspects 
of this requirement, including the true effectiveness of this 
requirement on reducing EtO emissions, any capital and annual costs 
that we did not account for, the time that is needed to comply with 
this requirement, and any other potential barriers to or impacts of 
imposing this requirement (Comment C-35).
9. Summary of Baseline Standards
    Pursuant to CAA sections 112(d)(2), 112(d)(3), and 112(d)(5), we 
are proposing standards for a number of currently unregulated EtO 
emission sources at commercial sterilizes.\35\ As mentioned earlier and 
described in more detail in sections III.C and III.D of this preamble, 
the EPA conducted a second section 112(f)(2) analysis for the source 
category. For that analysis, the EPA conducted a baseline risk 
assessment that took into account the current standards in subpart O as 
well as implementation of the proposed 112(d) standards for the 
currently unregulated emission sources discussed here in section III.B. 
Table 18 summarizes these standards.
---------------------------------------------------------------------------

    \35\ In addition, we are proposing a correction to the current 
standard under 112(d) for ARV at facilities where EtO use is at 
least 10 tpy.

[[Page 22824]]



    Table 18--Summary of Standards After Proposed Actions Pursuant to CAA Sections 112(d)(2), 112(d)(3), and
                                                    112(d)(5)
----------------------------------------------------------------------------------------------------------------
        Emission source           Existing or new?       EtO use              Standards           CAA section
----------------------------------------------------------------------------------------------------------------
SCV............................  Existing.........  At least 10 tpy..  99 percent emission     Current standard.
                                                                        reduction.
                                                    At least 1 but     99 percent emission     Current standard.
                                                     less than 10 tpy.  reduction.
                                                    Less than 1 tpy..  99 percent emission     112(d)(5).
                                                                        reduction.
                                 New..............  At least 10 tpy..  99 percent emission     Current standard.
                                                                        reduction.
                                                    At least 1 but     99 percent emission     Current standard.
                                                     less than 10 tpy.  reduction.
                                                    Less than 1 tpy..  99 percent emission     112(d)(5).
                                                                        reduction.
ARV............................  Existing.........  At least 10 tpy..  99 percent emission     Current standard.
                                                                        reduction.
                                                    At least 1 but     99 percent emission     112(d)(5).
                                                     less than 10 tpy.  reduction.
                                                    Less than 1 tpy..  99 percent emission     112(d)(5).
                                                                        reduction.
                                 New..............  At least 10 tpy..  99 percent emission     Current standard.
                                                                        reduction.
                                                    At least 1 but     99 percent emission     112(d)(5).
                                                     less than 10 tpy.  reduction.
                                                    Less than 1 tpy..  99 percent emission
                                                                        reduction.
CEV............................  Existing.........  At least 10 tpy..  3.2E-4 lb/hr..........  112(d)(2) and (3)
                                                    At least 1 but     99 percent emission     112(d)(5).
                                                     less than 10 tpy.  reduction.
                                                    Less than 1 tpy..  99 percent emission     112(d)(5).
                                                                        reduction.
CEV............................  New..............  At least 10 tpy..  3.2E-4 lb/hr..........  112(d)(2) and
                                                                                                (3).
                                                    At least 1 but     99 percent emission     112(d)(5).
                                                     less than 10 tpy.  reduction.
                                                    Less than 1 tpy..  99 percent emission     112(d)(5).
                                                                        reduction.
Group 1 room air emissions at    Existing and new.  N/A..............  1.3E-3 lb/hr \1\......  112(d)(2) and
 major sources.                                                                                 (3).
Group 1 room air emissions at    Existing and new.  N/A..............  1.3E-3 lb/hr \1\......  112(d)(5).
 area sources.
Group 2 room air emissions at    Existing and new.  N/A..............  2.8E-3 lb/hr \1\......  112(d)(2) and
 major sources.                                                                                 (3).
Group 2 room air emissions at    Existing.........  N/A..............  Follow either the       112(d)(5).
 area sources.                                                          Cycle Calculation
                                                                        Approach or the
                                                                        Bioburden/Biological
                                                                        Indicator Approach to
                                                                        achieve sterility
                                                                        assurance in
                                                                        accordance with ISO
                                                                        11135:2014 (July 15,
                                                                        2014) and ISO 11138-
                                                                        1:2017 (March
                                                                        2017)\2\.
                                 New..............  N/A..............  2.8E-3 lb/hr \1\......  112(d)(5).
----------------------------------------------------------------------------------------------------------------
\1\ We are also proposing to require each facility to operate areas with these emissions in accordance with the
  PTE requirements of EPA Method 204 of appendix M to 40 CFR part 51.
\2\ Owners and operators may also apply for an alternative means of emission limitation under CAA section
  112(h)(3).

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

    We conducted a risk assessment for the Commercial Sterilization 
Facilities source category using the risk assessment methods described 
in section II.F of this preamble. We present results of the risk 
assessment briefly below and in more detail in the Residual Risk 
Assessment for the Commercial Sterilization Facilities Source Category 
in Support of the 2022 Risk and Technology Review Proposed Rule, which 
is available in Docket ID No. EPA-HQ-OAR-2019-0178. The risk assessment 
was conducted on the 86 facilities in the commercial sterilization 
source category that are currently in operation and 11 research and 
development facilities, for a total of 97 facilities. To exercise 
caution with respect to this source category, we included research 
facilities in our assessment because there is a lack of certainty over 
whether these are true research facilities, for which CAA section 
112(c)(7) requires that a separate category be established. However, 
EtO use at these facilities tends to be very low (less than 1 tpy), and 
these facilities have low risk.
    All baseline risk results are developed using the best estimates of 
actual emissions and release parameters summarized in section II.F.1. 
Because allowable emissions and risks would be higher than actual 
emissions in this case, and in light of our finding that risks are 
unacceptable based on actual emissions, as discussed in section III.D.2 
of this preamble, a separate assessment of allowable emissions appears 
unnecessary.
    The results of the baseline chronic inhalation cancer risk 
assessment using actual emissions are shown in Table 19. The MIR is 
estimated to be 6,000-in-1 million, driven by EtO from Group 2 room air 
emissions (70 percent) and sterilization chamber vents (28 percent). 
The total estimated cancer incidence is 0.9 excess cancer case per 
year, or one cancer case every 13 months. The estimated population 
exposed to cancer risks between 1,000-in-1 million and the maximum risk 
level of 6,000-in-1 million is 900 people. The total population exposed 
to cancer risks greater than 100-in-1 million is 18,000 people. The 
population exposed to cancer risks greater than or equal to 1-in-1 
million living within 50 km of a facility is approximately 8.3 million 
(see Table 19 of this preamble). Of the 97 facilities that were 
assessed, 16 facilities have an estimated maximum cancer risk greater 
than 100-in-1 million and six of those facilities have an estimated 
maximum cancer risk greater than 1,000-in-1 million. The maximum 
chronic noncancer TOSHI for the source category is estimated to be 0.04 
(for neurological effects). The acute risk screening assessment of 
reasonable worst-case inhalation impacts indicates

[[Page 22825]]

a maximum acute HQ of 0.002 for PpO based on the REL acute health 
reference value. For EtO, the maximum HQ is 0.0005 based on the AEGL-2 
acute health reference value.\36\
---------------------------------------------------------------------------

    \36\ Acute RELs, ERPG-1, and AEGL-1 acute health reference 
values are not available for ethylene oxide.

                     Table 19--Sterilization Facilities Source Category Inhalation Risk Assessment Results Based on Actual Emissions
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                          Estimated       Estimated       Estimated
                                           Maximum      population at   population at   annual cancer
                                         individual    increased risk  increased risk     incidence         Maximum chronic      Maximum screening acute
                                         cancer risk   of cancer >100- of cancer >=1-    (cases per       noncancer TOSHI \1\          noncancer HQ
                                       (in 1 million)   in-1  million   in-1 million        year)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Source Category......................           6,000          18,000       8,300,000             0.9  0.04 (Neurological).....  0.002 (REL).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ The TOSHI is the sum of the chronic noncancer HQs for substances that affect the same target organ or organ system.

    An assessment of facility-wide (or ``whole facility'') risks was 
performed to characterize the source category risk in the context of 
whole facility risks. Non-source category emissions were estimated 
using the EPA's 2017 NEI as described in section II.F.6. The facility-
wide assessment showed that risks from non-source category emission 
sources were minimal. The MIR, populations above cancer risk 
thresholds, incidence, and maximum chronic noncancer TOSHI in the 
facility-wide risk assessment were the same as the source category risk 
assessment (Table 19). We also examined areas surrounding sterilization 
facilities for other significant emission sources of HAP. That analysis 
determined that the vast majority of sterilization facilities are not 
located nearby other significant sources of HAP as most are isolated or 
located within office parks.\37\
---------------------------------------------------------------------------

    \37\ EPA Air Toxics Screening Assessment (AirToxScreen). 
Available at: https://www.epa.gov/AirToxScreen.
---------------------------------------------------------------------------

    We then repeated our risk assessment for the Commercial 
Sterilization Facilities source category assuming emission reductions 
under CAA sections 112(d)(2), 112(d)(3), and 112(d)(5) as described 
above and summarized in Table 18, with the exception of the proposed 
Group 1 room air emission standards. Instead, the risk assessment was 
based on requiring BMP (Option 2) under section 112(d)(5) for Group 1 
room air emissions, which we had initially considered proposing instead 
of an emission limit reflecting use of control devices (Option 1); 
however, following our risk assessment, we continued to review our 
regulatory options and determined that the emission limit reflecting 
use of control devices (Option 1) is a more appropriate option than the 
BMP for Group 1 room air emissions for the reason discussed in section 
III.B.8. We are therefore proposing such emission limit instead of the 
BMP under section 112(d)(5). While we have not reassessed risks based 
on this one change in a proposed section 112(d)(5) standard, we do not 
expect this change to affect the MIR for the source category in this 
scenario, as it was driven by Group 2 room air emissions and 
sterilization chamber vent emissions, although we anticipate that one 
or more of the other results presented in Table 20 may be lower (e.g., 
populations at various risk thresholds and cancer incidence).
    In the scenario assuming emission reductions under the proposed CAA 
sections 112(d)(2), 112(d)(3), and 112(d)(5),\38\ the MIR is estimated 
to be 3,000-in-1 million driven by EtO from Group 2 room air emissions 
(70 percent) and sterilization chamber vents (28 percent). The total 
estimated cancer incidence is 0.3 excess cancer case per year, or one 
cancer case every 3.3 years. The estimated population exposed to cancer 
risks between 1,000-in-1 million and the maximum risk level of 3,000-
in-1 million is 200 people, down from 900 people in the baseline 
scenario. The total population exposed to cancer risks greater than 
100-in-1 million is 2,350 people, down from 18,000 people in the 
baseline scenario. The population exposed to cancer risks greater than 
or equal to 1-in-1 million living within 50 km of a facility is 
approximately 3.2 million, down from 8.3 million. Of the 97 facilities 
that were assessed, 13 facilities have an estimated maximum cancer risk 
greater than 100-in-1 million (down from 16) and two of those 
facilities have an estimated maximum cancer risk greater than 1000-in-1 
million (down from six). The maximum chronic noncancer TOSHI for the 
source category is estimated to be 0.003 for the neurological target 
organ. The acute risk screening assessment of reasonable worst-case 
inhalation impacts indicates a maximum acute HQ of 0.001 for propylene 
oxide (PpO) based on the REL acute health reference value. For EtO, the 
maximum HQ is 0.0003 based on the AEGL 2 acute health reference 
value.\39\
---------------------------------------------------------------------------

    \38\ As explained immediately above, the risk assessment assumed 
emission reductions from the BMP option (Option 2) for Group 1 room 
air emissions, and that based on further analysis following the risk 
assessment, we are proposing the emission limit reflecting use of 
control devices (Option 1) instead of the BMP option assumed in the 
risk assessment.
    \39\ RELs, ERPG-1, and AEGL-1 acute health reference values are 
not available for ethylene oxide.

[[Page 22826]]



   Table 20--Sterilization Facilities Source Category Inhalation Risk Assessment Results Based on Actual Emissions After Emission Reductions Under CAA
                                                      Sections 112(d)(2), 112(d)(3), and 112(d)(5)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                          Estimated       Estimated       Estimated
                                           Maximum      population at   population at   annual cancer
                                         individual    increased risk  increased risk     incidence         Maximum chronic      Maximum screening acute
                                         cancer risk   of cancer >100- of cancer >=1-    (cases per       noncancer TOSHI \1\          noncancer HQ
                                       (in 1 million)   in-1  million   in-1 million        year)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Source category......................           3,000       \2\ 2,350   \2\ 3,200,000         \2\ 0.3  0.003 (Neurological)....  0.001 (REL).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ The TOSHI is the sum of the chronic noncancer HQs for substances that affect the same target organ or organ system.
\2\ These values may be lower due to the proposed Group 1 room air emission standards that were not included in the risk assessment.

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

    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'' (54 FR 38045, September 14, 1989). For this 
proposal, the EPA estimated baseline risks based on actual emissions 
from the Commercial Sterilization Facilities source category, as well 
as emission reductions from the proposed standards for the currently 
unregulated emissions sources under CAA sections 112(d)(2), 112(d)(3), 
and 112(d)(5) as described above and summarized in Table 18. For the 
purposes of risk acceptability, we considered the risks after the 
emission reductions under CAA sections 112(d)(2), 112(d)(3), and 
112(d)(5).
1. Determination of Risk Acceptability After Emission Reductions Under 
CAA Sections 112(d)(2), 112(d)(3), and 112(d)(5)
    As noted in section II.D of this preamble, we weigh a wide range of 
health risk measures and factors in our risk acceptability 
determination, including the cancer MIR, the number of persons in 
various cancer and noncancer risk ranges, cancer incidence, the maximum 
noncancer TOSHI, the maximum acute noncancer HQ, the extent of 
noncancer risks, the distribution of cancer and noncancer risks in the 
exposed population, and risk estimation uncertainties (54 FR 38044, 
September 14, 1989).
    For the Commercial Sterilization Facilities source category, the 
risk results indicate that the cancer risks to the individual most 
exposed are well above 100-in-1 million, which is the presumptive upper 
end of the range of acceptability. The estimated inhalation cancer risk 
to the individual most exposed to emissions from the source category is 
3,000-in-1 million after emission reductions under CAA sections 
112(d)(2), 112(d)(3), and 112(d)(5). The estimated incidence of cancer 
due to inhalation exposures is 0.3 excess cancer case per year. The 
population estimated to be exposed to cancer risks greater than 100-in-
1 million is approximately 2,350, and the population estimated to be 
exposed to cancer risks greater than or equal to 1-in-1 million is 
approximately 3.2 million. The estimated maximum chronic noncancer 
TOSHI from inhalation exposure for this source category is 0.003 (for 
neurological effects), indicating low likelihood of adverse noncancer 
effects from long-term inhalation exposures. The acute risk screening 
assessment of reasonable worst-case inhalation impacts indicates a 
maximum acute HQ of 0.001. Therefore, we conclude that adverse effects 
from acute exposure to emissions from this category are not 
anticipated.
    Considering the health risk information and factors discussed 
above, particularly the high MIR for the source category, we propose to 
find that the risks from the Commercial Sterilization Facilities source 
category, taking into account emission reductions under CAA sections 
112(d)(2), 112(d)(3), and 112(d)(5) as described above and summarized 
in Table 18, are unacceptable. As noted in section II.A of this 
preamble, when risks are unacceptable, the EPA must determine the 
emissions standards necessary to reduce risk to an acceptable level. 
Therefore, pursuant to CAA section 112(f)(2), we are proposing certain 
standards that are more protective than those shown in Table 18 based 
on our proposed finding that risks from this source category remain 
unacceptable even after the application of revised standards under 
section 112(d).
a. Available Controls To Address Risks
    We evaluated several control options for reducing risks. Based on 
the results of the risk assessment, we have identified SCVs and Group 2 
room air emissions as the primary contributors to risks. Therefore, we 
focused our analysis of control options on SCVs and Group 2 room air 
emissions to reduce risk.
    As mentioned above, the MIR for the source category is estimated to 
be 3,000-in-1 million, driven by EtO from one facility. Results from 
our risk assessment indicate that, for that facility with the source 
category MIR of 3,000-in-1 million, 28 percent of the risk is from 
SCVs. The remaining risk is mostly from Group 2 room air emissions (70 
percent).
    This facility is the only one within the source category where the 
emissions from SCVs contribute to the facility's MIR exceeding 100-in-1 
million, and this facility currently uses 44 tpy of EtO. The current 
subpart O requires 99 percent emission reduction for SCVs at facilities 
where EtO use is at least 1 tpy. An emission reduction of 99 percent is 
also the proposed standard under CAA section 112(d)(5) for the 
currently unregulated SCVs, which are those facilities where EtO use is 
less than 1 tpy (see section III.B.1.a).
    Our data do not identify any add-on controls beyond those we have 
already considered when promulgating the SCV standards in subpart O or 
proposing the standards for the currently unregulated SCV standards in 
section II.B.1. However, our evaluation of the performance data shows 
that these controls can achieve greater than 99 percent reduction. We 
therefore considered a more stringent SCV standard for facilities where 
EtO use is at least 40 tpy, which would include the one and only 
facility where the emissions from SCVs contribute to the facility's MIR 
exceeding 100-in-1 million. The emission limit that we evaluated is 
99.94 percent reduction, which would reduce this facility's SCV 
emissions such that they no longer contribute to this facility's MIR 
exceeding 100-in-a-million.\40\ We have

[[Page 22827]]

determined that this is feasible because our evaluation of performance 
tests indicates that 27 out of 36 facilities with SCVs and using at 
least 40 tpy of EtO are already exceeding this emission reduction from 
their SCVs. Of those 27 facilities, 14 use wet scrubbers, six use 
catalytic oxidizers, four use a wet scrubber and gas/solid reactor in 
series, two use thermal oxidizers, and one uses a wet scrubber and 
catalytic oxidizer in series.
---------------------------------------------------------------------------

    \40\ As mentioned above, the remaining risks from this facility 
are from Group 2 room air emissions, which we will address 
immediately below in the next subsection.
---------------------------------------------------------------------------

    As mentioned above, results from our risk assessment indicate that, 
for the facility with the source category MIR of 3,000-in-1 million, 70 
percent of the risk is from Group 2 room air emissions. In addition to 
this facility, which is an area source, there are two other facilities, 
also area sources, where Group 2 room air emissions contribute to the 
facilities' MIRs exceeding 100-in-1 million.\41\ Because Group 2 room 
air emissions are one of the two principal contributors to unacceptable 
risks from existing area sources in this source category, we evaluated 
available control options for reducing risks from Group 2 room air 
emissions.
---------------------------------------------------------------------------

    \41\ As discussed earlier, the EPA has the authority to conduct 
an (f)(2) review of GACT standards and is exercising that authority 
in this action.
---------------------------------------------------------------------------

    As discussed in section III.B.8.g of this preamble, we are 
proposing a GACT standard for currently unregulated Group 2 room air 
emissions at existing area source facilities. Specifically, we are 
proposing under CAA section 112(d)(5) that facilities follow either the 
Cycle Calculation Approach or the Bioburden/Biological Indicator 
Approach to achieve sterility in accordance with ISO 11135:2014 and ISO 
11138-1:2017 is not exceeded.\42\
---------------------------------------------------------------------------

    \42\ As discussed in section III.B.8 of this preamble, we are 
proposing an emission rate of 2.8E-3 lb/hr for all new area source 
facilities, regardless of EtO use, under CAA section 112(d)(5).
---------------------------------------------------------------------------

    In proposing this standard, we also considered an emission rate of 
2.8E-3 lb/hr that reflects the use of control devices (Option 1) but 
did not propose that option based on our analysis of relevant factors 
under section 112(d)(5). However, having proposed to determine under 
CAA section 112(f)(2) that the risk for the source category is 
unacceptable, we must determine the emissions standards necessary to 
reduce risk to an acceptable level without considering costs. 
Therefore, we are considering under section 112(f)(2) this emission 
rate of 2.8E-3 lb/hr for reducing risks from existing area source 
facilities where EtO use is at least 20 tpy, which would include all 
three facilities where the Group 2 room air emissions contribute to 
these facilities' MIRs exceeding 100-in-1 million.\43\
---------------------------------------------------------------------------

    \43\ The EtO usage at these three facilities range from 22 to 77 
tpy.
---------------------------------------------------------------------------

    Another option for reducing Group 2 room air emissions is setting a 
work practice standard to limit both the maximum volumetric flow rate 
and maximum EtO concentration of the exhaust streams that contain these 
emissions. Based on our estimate, this work practice standard would 
reduce emissions below the 2.8E-3 lb/hr limit. We note that if both the 
volumetric flow rate and EtO concentration are restricted, there are at 
least two potential outcomes. One outcome is that a facility could keep 
the volume of the enclosure constant but restrict the number of room 
air changes (RACs) per hour. This could potentially result in an 
increase in EtO concentration within the enclosure. In order to 
maintain personnel safety, significant upgrades and changes may need to 
be made, which could require significant costs. Another outcome is that 
the facility could keep the number of RACs per hour constant but 
restrict the volume of the enclosure. Both of these outcomes could 
result in a reduced capacity to sterilize medical products, which is an 
important consideration in light of the role that sterilization 
facilities play in the medical supply chain.
b. Regulatory Options
    We considered more stringent SCV and Group 2 room air emission 
standards to reduce risk from the source category to an acceptable 
level. To that end, we identified the following two options. Control 
Option 1 would require that (1) facilities where EtO use is at least 40 
tpy reduce emissions from individual SCVs by 99.94 percent; and (2) 
area source facilities where EtO use is at least 20 tpy limit the Group 
2 room air EtO emission rate to 2.8E-3 lb/hr. Control Option 2 would 
have the same two requirements as Option 1, except that the 2.8E-3 lb/
hr limit would not apply to facilities with MIR remaining greater than 
100-in-1 million even after the imposition of the requirements under 
Control Option 1, as determined by this risk assessment, and detailed 
in Appendix 10 of the document titled Residual Risk Assessment for the 
Commercial Sterilization Facilities Source Category in Support of the 
2022 Risk and Technology Review Proposed Rule, which is available in 
the docket for this rulemaking. For these two facilities,\44\ Option 2 
would require work practice standards that would reduce Group 2 room 
air emissions at these two facilities to a level that would lower their 
MIR to 100-in-1-million, based on our estimates. Under this work 
practice standard, Group 2 room air emissions would be limited to a 
maximum volumetric flow rate of 2,900 dscfm and a maximum EtO 
concentration of 30 ppbv.
---------------------------------------------------------------------------

    \44\ As explained below in section III.D.1.c, following our risk 
modeling, which showed 3 facilities in this group, we conducted 
additional analysis that resulted in stricter proposed standards 
under section 112(d)(5) for Group 1 room air emissions, which in 
turn changed the number of facilities (from three to two) that, 
after taking into account emission reduction from Option 1, would 
still have an MIR > 100-in-a-million due to group 2 room air 
emissions.
---------------------------------------------------------------------------

    In considering the work practice standards described above, it is 
important to understand the uncertainties related to the modeled EtO 
emissions for the two area source facilities that would be subject to 
these standards. For one facility, we did not receive any room area or 
EtO monitoring data as part of the September 2021 ICR that could have 
been used to quantify Group 2 room air emissions. Therefore, we modeled 
emissions using our default assumption that 0.2 percent of EtO used is 
emitted as part of Group 2 room air emissions. In addition, we did not 
receive any information on how the air for areas where there are Group 
2 room air emissions is leaving the facility (i.e., the height, 
temperature, diameter, velocity, and flow rate of each release point 
for these areas). Therefore, Group 2 room air emissions were modeled as 
an area source. These factors increase the uncertainty of the MIR for 
this facility. For the other facility, we understand that a new 
approval order has recently been issued for this facility that includes 
limits on Group 2 room air emissions.\45\ However, we do not know how 
the dispersion characteristics for these emissions will change upon the 
installation of additional controls. This increases the uncertainty of 
the MIR for this facility.
---------------------------------------------------------------------------

    \45\ https://eqedocs.utah.gov/TempEDocsFiles/142039467_142039467_AgencyInterest_10301-10400_10377%20-%20BD%20Medical-%20Medical%20Device%20Manufacturing%20Plant_New%20Source%20Review_2022_DAQ-2022-008635.pdf.
---------------------------------------------------------------------------

c. Determination of Risk Acceptability After Emission Reductions Under 
CAA Section 112(f)(2)
    As discussed above, we consider two options for reducing risks. 
Control Option 1 would require (1) 99.94 percent emission reduction for 
each SCV at facilities using at least 40 tpy EtO and (2) 2.8E-3 lb/hr 
emission limit for Group 2 room air emissions at area source facilities 
using at least 20 tpy. Control Option 2 would require (1)

[[Page 22828]]

99.94 percent emission reduction for each SCV at facilities using at 
least 40 tpy EtO; (2) 2.8E-3 lb/hr emission limit for Group 2 room air 
emissions at area source facilities using at least 20 tpy, except for 2 
facilities with MIR > 100-in-1-million after imposition of the 
requirements under Control Option 1; and (3) for these two facilities, 
work practice standards that would bring their MIR to 100-in-1-million.
    In Table 21, we present the risks after the implementation of 
Control Options 1 and 2 based on our risk assessment. The risk metrics 
shown in the table include the cancer MIR, population exposed to cancer 
risks greater than 100-in-1 million, population exposed to cancer risks 
greater than or equal to 1-in-1 million, and the cancer incidence.

   Table 21--Post-Control Risk Assessment Results for the Commercial Sterilization Facilities Source Category
----------------------------------------------------------------------------------------------------------------
                                                                     Estimated       Estimated       Estimated
                                                      Maximum      population at   population at   annual cancer
             Control option scenario                individual    increased risk  increased risk     incidence
                                                    cancer risk   of cancer >100- of cancer >=1-    (cases per
                                                  (in-1-million)   in-1 million    in-1 million        year)
----------------------------------------------------------------------------------------------------------------
Option 1........................................             400             ~33   \1\ 1,290,000         \1\ 0.2
Option 2........................................             100               0   \1\ 1,260,000         \1\ 0.1
----------------------------------------------------------------------------------------------------------------
\1\ These values may be lower because the proposed Group 1 room air emission standards were not applied or
  accounted for in the risk assessment.

    Control Option 1 reduces the MIR from 3,000-in-1 million to 400-in-
1-million. The total number of facilities posing cancer risks greater 
than 100-in-1 million would drop from 13 facilities at baseline after 
emission reductions under CAA sections 112(d)(2), 112(d)(3), and 
112(d)(5) to 3 facilities (two in Puerto Rico and one in Utah). We note 
that 1 of those 3 facilities would be subject to the proposed Group 1 
room air emission standards that were not included in the risk 
assessment and its risks would be below 100-in-1 million (but it would 
not impact the source category MIR). Additionally, the baseline 
population exposed to risk levels greater than 100-in-1 million would 
be reduced from 2,350 people to approximately 33 people. The total 
population exposed to risk levels greater than or equal to 1-in-1 
million living within 50 km of a facility would be reduced from 3.2 
million people to 1.29 million people. The total estimated cancer 
incidence of 0.9 drops to 0.2 excess cancer cases per year in Control 
Option 1. We note that the populations at risk levels greater than or 
equal to 1-in-1 million and the cancer incidence may be lower because 
the proposed Group 1 room air emission standards were not applied or 
accounted for in the risk assessment. Control Option 2 further reduces 
the MIR to 100-in-1million, with no facilities or populations at risk 
levels greater than 100-in-1 million. The total population exposed to 
risk levels greater than or equal to 1-in-1 million living with 50 km 
of a facility would be further reduced to 1.26 million people. Finally, 
in Control Option 2, the total estimated cancer incidence would be 
further reduced to 0.1 excess cancer cases per year. Again, the 
populations at risk levels greater than or equal to 1-in-1 million and 
the cancer incidence may be lower because the risk assessment did not 
account for the proposed Group 1 room air emission standards.
    In summary, both Control Options 1 and 2 would provide significant 
health benefits by reducing the cancer MIR from 3,000-in-1 million in 
the baseline after emission reductions under CAA sections 112(d)(2), 
112(d)(3), and 112(d)(5) to 400-in-1 million in Control Option 1 and to 
100-in-1 million in Control Option 2. That said, as noted earlier in 
this section, the EPA considers an MIR of ``approximately 1-in-10 
thousand'' to be the presumptive limit of acceptability (54 FR 38045, 
September 14, 1989). Therefore, because Control Option 2 provides an 
MIR at the presumptive limit of 1-in-10 thousand (or 100-in-1 million), 
we are proposing that Control Option 2 reduces risks to an acceptable 
level. We expect that 40 facilities will be affected by the proposed 
standards of Control Option 2, 36 of these 40 facilities will be 
subject to the SCV provisions, and all of these 40 facilities are 
expected to be subject to the provisions for Group 2 room air 
emissions. We solicit comment on the proposed requirements for SCVs and 
Group 2 room air emissions, including whether we should apply the 
limits on volumetric flow rate and EtO concentration at facilities 
where MIR is greater than 100-in-1 million after implementation of 
Control Option 1 to all Group 2 room air emissions at facilities where 
EtO use is at least 20 tpy (Comment C-36). In addition, for the same 
reason discussed above in section III.B.1.a, we solicit comment on 
whether to include an alternative lb/hr limit that is equivalent to 
99.94 percent emission reduction for SCVs at facilities where EtO use 
is at least 40 tpy and whether 3.1E-3 lb/hr, which we calculated using 
the method described in section III.B.1.a, is an appropriate 
alternative standard that is equivalent to the proposed 99.94 percent 
emission reduction standard for SCVs at facilities where EtO use is at 
least 40 tpy (Comment C-37). We also solicit comment on whether we 
should determine that Control Option 1 would reduce risks to an 
acceptable level, because, while the MIR is 400-in-1 million, the 
population exposed to risk levels above 100-in-1 million is low (~33 
people) and the population exposed to risks >=1-in-1 million is similar 
to Control Option 2 (1,290,000 people in Control Option 1 and 1,260,000 
people in Control Option 2) (Comment C-38).
2. Ample Margin of Safety
    The second step in the residual risk decision framework is 
determination of whether the emission standards proposed to achieve an 
acceptable risk level would protect public health with an ample margin 
of safety, or whether more stringent emission standards would be 
required. In making this determination, we considered the estimate of 
health risk and other health information, along with additional factors 
relating to the appropriate level of control, including costs and 
economic impacts of controls, technological feasibility, uncertainties, 
and other relevant factors, consistent with the approach of the 1989 
Benzene NESHAP.
    As discussed in the previous section, SCVs and Group 2 room air 
emissions

[[Page 22829]]

are the primary contributors to risks. At step 1 of our review of 
residual risks under section 112(f), we determined that more stringent 
standards for SCVs at facilities with EtO usage of at least 40 tpy and 
Group 2 room air emissions at area source facilities with EtO usage of 
at least 20 tpy are necessary to reduce risks to an acceptable level. 
For step 2 of our review of residual risks, which requires EPA to 
evaluate whether more stringent standards are necessary to provide an 
ample margin of safety to protect public health, we considered 
additional options to further reduce emissions from SCVs and Group 2 
room air emissions.
    Table 22 of this preamble presents the summary of costs and EtO 
emission reductions we estimated for the control options we considered, 
which are described immediately following the table. For details on the 
assumptions and methodologies used in the costs and impacts analyses, 
see the technical memorandum titled Technical Support Document for 
Proposed Rule--Industry Profile, Review of Unregulated Emissions, CAA 
Section 112(d)(6) Technology Review, and CAA Section 112(f) Risk 
Assessment for the Ethylene Oxide Emissions Standards for Sterilization 
Facilities NESHAP, which is available in the docket for this 
rulemaking.

     Table 22--Nationwide Emission Reductions and Cost Impacts of Control Options Considered for Commercial
                         Sterilization Facilities in the Ample Margin of Safety Analysis
----------------------------------------------------------------------------------------------------------------
                                                                      Total       EtO emission         Cost
                 Control option                   Total capital    annualized      reductions     effectiveness
                                                 investment ($)   costs ($/yr)        (tpy)        ($/ton EtO)
----------------------------------------------------------------------------------------------------------------
A--99.94 percent emission reduction requirement        $737,689        $266,687            0.17       $1,531,726
 for SCVs at facilities where EtO use is at
 least 10 tpy but less than 40 tpy.............
B--99.6 percent emission reduction requirement                0               0               0              N/A
 for SCVs at facilities where EtO use is at
 least 10 tpy but less than 40 tpy (prevent
 backsliding)..................................
C--99.8 percent emission reduction requirement           92,211          34,939          1.8E-2        1,947,753
 for SCVs at facilities where EtO use is at
 least 1 tpy but less than 10 tpy..............
D--99.2 percent emission reduction requirement                0               0               0              N/A
 for SCVs at facilities where EtO use is at
 least 1 tpy but less than 10 tpy (prevent
 backsliding)..................................
E--99.3 percent emission reduction requirement          368,845          92,295          3.4E-2        2,724,634
 for SCVs at facilities where EtO use is less
 than 1 tpy....................................
F--Limit Group 2 room air emissions to a             28,542,825       2,861,119            1.52        1,883,935
 maximum volumetric flow rate of 2,900 dscfm
 and a maximum EtO concentration of 30 ppbv \1\
G--Existing Group 2 room air emission limit of       98,400,887      10,648,525          5.5E-2      194,111,365
 2.8E-3 lb/hr at area source facilities where
 EtO use is less than 20 tpy...................
----------------------------------------------------------------------------------------------------------------
\1\ As discussed later in this section, these costs only include PTE and do not include the costs of upgrades
  and changes needed to maintain personnel safety or potential revenue losses from a reduced capacity to
  sterilize product.

    As mentioned earlier, available performance data show controls for 
reducing SCV emissions have much improved. We therefore consider 
potential options to further reduce SCV emissions. We considered two 
options for SCVs at facilities where EtO use is at least 10 tpy but 
less than 40 tpy (Control Options A and B). Under Control Option A, we 
considered 99.94 percent emission reduction for SCVs at facilities 
where EtO use is at least than 10 tpy but less than 40 tpy. This is the 
same limit as that we are proposing for all facilities where EtO use is 
at least 40 tpy in order to bring the source category risk to an 
acceptable level. Under Control Option B, we considered the maximum SCV 
emission reduction that all facilities where EtO use is at least 10 tpy 
but less than 40 tpy are currently meeting. This emission reduction is 
99.6 percent. We also considered two options for SCVs at facilities 
where EtO use is at least 1 tpy but less than 10 tpy (Control Options C 
and D). Under Control Option C, we considered the maximum SCV emission 
reduction with which compliance can be demonstrated \46\ at all 
facilities where EtO use is at least 1 tpy but less than 10 tpy 
considering current emission profiles. This emission reduction is 99.8 
percent. Under Control Option D, we considered the maximum SCV emission 
reduction that all facilities where EtO use is at least 1 tpy but less 
than 10 tpy are currently meeting. This emission reduction is 99.2 
percent. We identified one option for SCVs at facilities where EtO use 
is less than 1 tpy. Specifically, under Control Option E, we considered 
the maximum SCV emission reduction for which compliance can be 
demonstrated at all facilities where EtO use is less than 1 tpy 
considering current emission profiles. This emission reduction is 99.3 
percent. The ample margin of safety analysis for these options is 
discussed below.
---------------------------------------------------------------------------

    \46\ i.e., Based on facility characteristics, there is no 
compliance demonstration issue because the required EtO 
concentration to meet this limit would be at or above 30 ppbv (3 x 
RDL).
---------------------------------------------------------------------------

    As mentioned above, Control Options A and B address SCVs at 
facilities where EtO use is at least 10 tpy but less than 40 tpy. For 
Control Option A, which would require 99.94 percent emission reduction 
for SCVs at all facilities where EtO use is at least 10 tpy but less 
than 40 tpy, we found a total capital cost of $737,689 and a total 
annualized cost of $266,687. The estimated EtO emissions reductions are 
0.17 tpy with a cost effectiveness of $1,531,726 per ton of EtO. While 
we do not know what the full extent of risk reductions would be, we 
expect that some risk reduction would occur as a result of reduced EtO 
emissions.
    Control Option B would require 99.6 percent emission reduction 
(reflecting the maximum reduction that all facilities within this EtO 
usage amount are meeting). While there would be no costs, there would 
also be no further reductions in emissions and in turn no further 
reductions in risks; at best Option B would simply prevent backsliding 
in the performance of current SCV emission controls at these 
facilities. In light of the above, we believe that Option A would be a 
better choice than Option B for further reducing emissions from SCVs at 
facilities where EtO use is at least 10 tpy but less than 40 tpy.

[[Page 22830]]

    Control Options C and D address SCVs at facilities where EtO use is 
at least 1 tpy but less than 10 tpy. For Control Option C, which would 
require 99.8 percent emission reduction (reflecting the maximum 
reduction with which compliance can be demonstrated at all facilities 
where EtO use is at least 1 tpy but less than 10 tpy), we determined a 
total capital cost of $92,211 and a total annualized cost of $34,939. 
The estimated EtO emissions reductions are 1.8E-2 tpy with a cost 
effectiveness of $1,947,753 per ton of EtO. While we do not know what 
the full extent of risk reductions would be, we expect that some risk 
reduction would occur as a result of reduced EtO emissions.
    Control Option D would require 99.2 percent emission reduction 
(reflecting the maximum reduction that all facilities within this EtO 
usage amount are meeting). While there would be no costs, there would 
also be no reductions in emissions and in turn no reductions in risks; 
at best Option D would simply prevent backsliding in the performance of 
current SCV emission controls at these facilities. In light of the 
above, we believe that Option C would be a better choice than Option D 
for further reducing emissions from SCVs at facilities where EtO use is 
at least 1 tpy but less than 10 tpy.
    Control Option E addresses SCVs at facilities where EtO use is less 
than 1 tpy. Specifically, Control Option E would require that these 
facilities reduce emissions from each SCV by 99.3 percent (the maximum 
emission reduction with which compliance can be demonstrated at all 
facilities using less than 1 tpy). We expect that some risk reduction 
would occur as a result of reduced EtO emissions but do not know what 
the full extent of risk reductions would be. The costs were found to be 
a $368,845 total capital investment and a $92,295total annualized cost. 
The estimated EtO emissions reductions are 3.4E-2 tpy with a cost 
effectiveness of $2,724,634 per ton of EtO. Our established methodology 
for assessing economic impacts of regulations indicates that the 
potential for adverse economic impacts begins when the cost to sales 
ratio exceeds five percent. Considering Control Option E, along with 
the standards that we have proposed up to this point, the cost to sales 
ratio for one company operating a facility where EtO use is less than 1 
tpy would be 11 percent, far exceeding our estimated five percent at 
which point the potential for adverse economic impacts begins. Based on 
the available economic information, assuming market conditions remain 
approximately the same, we are concerned that this company would not be 
able to sustain the costs associated with any additional control 
requirements.
    We consider two potential options to further reduce Group 2 room 
air emissions (Control Options F and G). Under Control Option F, Group 
2 room air emissions would be limited to a maximum volumetric flow rate 
of 2,900 dscfm and a maximum EtO concentration of 30 ppbv at all 
facilities. These are the same limits as that we are proposing for 
facilities where MIR is greater than 100-in-1 million after 
implementation of Control Option 1 in order to bring the source 
category risk to an acceptable level.\47\ Under Control Option G, 
existing Group 2 room air emissions would be limited to 2.8E-3 lb/hr at 
area source facilities where EtO use is less than 20 tpy. This is the 
same limit as that we are proposing for all facilities where EtO use is 
at least 20 tpy (except for facilities where MIR is greater than 100-
in-1 million after implementation of Control Option 1) to bring the 
source category risk to an acceptable level. The ample margin of safety 
analysis for these options is discussed below.
---------------------------------------------------------------------------

    \47\ As explained in section III.C.1, reducing the source 
category risk to an acceptable level would require a separate and 
more stringent standard for these two facilities.
---------------------------------------------------------------------------

    Under Control Option F, which would require that Group 2 room air 
emissions be limited to a maximum volumetric flow rate of 2,900 dscfm 
and a maximum EtO concentration of 30 ppbv at all facilities, we were 
unable to fully estimate costs because it is unknown how this would 
affect operations. As discussed in section III.C.1.a, if both the 
volumetric flow rate and EtO concentration are restricted, there are at 
least two potential outcomes. One outcome is that a facility could keep 
the volume of the enclosure constant but restrict the number of RACs 
per hour. This could potentially result in an increase in EtO 
concentration within the enclosure. In order to maintain personnel 
safety, significant upgrades and changes may need to be made, which 
could require significant costs. Another outcome is that the facility 
could keep the number of RACs per hour constant but restrict the volume 
of the enclosure. While both outcomes could result in potential costs 
savings from reduced air handling, this may be offset by a loss a 
revenue from a reduced capacity to sterilize product. This could also 
impact the supply of medical devices. We did not consider this a viable 
option in light of the potentially adverse safety, production capacity, 
and cost implications of this option as described above.
    Under Control Option G, which would limit Group 2 room air emission 
to 2.8E-3 lb/hr at area source facilities where EtO use is less than 20 
tpy \48\ costs were found to be a $98,400,887 total capital investment 
and a $10,648,525 total annualized cost. The estimated EtO emissions 
reductions are 5.5E-2 tpy with a cost effectiveness of $194,111,365 per 
ton of EtO. While we do not know what the full extent of risk 
reductions would be, we expect that some risk reduction would occur as 
a result of reduced EtO emissions. However, the cost to sales ratio for 
three companies operating three facilities where EtO use is less than 
20 tpy would range from 17 to 56 percent, far exceeding our estimated 
five percent at which point the potential for adverse economic impacts 
begins. Based on the available economic information, assuming market 
conditions remain approximately the same, we are concerned that these 
companies would not be able to sustain the costs associated with any 
additional control requirements.
---------------------------------------------------------------------------

    \48\ This is the proposed MACT standard for Group 2 room air 
emissions at major sources; it is also our proposed standard for 
Group 2 room air emissions at area source facilities where EtO usage 
is at least 20 tpy.
---------------------------------------------------------------------------

    Based on our ample margin of safety analysis, including all health 
information and the associated cost and feasibility as discussed above, 
we propose that requiring the standards that based on our analysis 
would bring risks to an acceptable level, along with Control Options A 
and C here in the present analysis, would provide an ample margin of 
safety to protect public health. These standards, which we are 
proposing under the AMOS analysis, consist of 99.94 percent reduction 
for SCVs at facilities where EtO use is at least 10 tpy but less than 
40 tpy, as well as 99.8 percent emission reduction for SCVs at 
facilities where EtO use is at least 1 tpy but less than 10 tpy. We are 
soliciting comment on our proposed determination, including whether 
Control Options B, D, E, F, or G would provide an ample margin of 
safety to protect public health. (Comment C-39). In addition, for the 
same reason discussed above in section III.B.1.a, we solicit comment on 
whether to include an alternative lb/hr limit that is equivalent to 
99.94 percent emission reduction for SCVs at facilities where EtO use 
is at least 10 tpy but less than 40 tpy, and whether 1.2E-3 lb/hr for 
existing sources and 1.0E-3 lb/hr for new sources, which we calculated 
using

[[Page 22831]]

the method described in section III.B.1.a, are appropriate alternative 
standards that are equivalent to the proposed 99.94 percent emission 
reduction standard for SCVs at facilities where EtO use is at least 10 
tpy but less than 40 tpy. Similarly, we solicit comment on whether to 
include alternative lb/hr limits that are equivalent to 99.8 percent 
emission reduction for SCVs at facilities where EtO use is at least 1 
tpy but less than 10 tpy, and whether 7.2E-4 lb/hr for existing sources 
and 5.5E-4 lb/hr for new sources, which we calculated using the method 
described in section III.B.1.a, are appropriate alternative standards 
that are equivalent to the proposed 99.8 percent emission reduction 
standard for SCVs at facilities where EtO use is at least 1 tpy but 
less than 10 tpy (Comment C-40).
3. Environmental Effects
    The emissions data indicate that no environmental HAP are emitted 
by sources within this source category. In addition, we are unaware of 
any adverse environmental effects caused by HAP emitted by this source 
category. Therefore, we do not expect there to be an adverse 
environmental effect as a result of HAP emissions from this source 
category and we are proposing that it is not necessary to set a more 
stringent standard to prevent, taking into consideration costs, energy, 
safety, and other relevant factors, an adverse environmental effect.
4. Summary of Proposed Standards
    Pursuant to CAA sections 112(d)(2), 112(d)(3), and 112(d)(5), we 
are proposing standards for a number of currently unregulated EtO 
emission sources at commercial sterilizers.\49\ The EPA also conducted 
a section 112(f)(2) analysis. For that analysis, the EPA conducted a 
baseline risk assessment that took into account the implementation of 
the current standards in subpart O as well as the proposed 112(d) 
standards for the currently unregulated emission sources discussed here 
in section III.B. Having proposed to determine that the risk is 
unacceptable for the source category, the EPA is proposing under 
section 112(f)(2) standards, including tightening certain proposed 
section 112(d) standards, to bring the risk from this source category 
to an acceptable level and provide ample margin of safety to protect 
public health. Table 23 summarizes the proposed section 112(d) and 
112(f)(2) standards.
---------------------------------------------------------------------------

    \49\ In addition, we are proposing a correction to the current 
standard under 112(d) for ARV at facilities with EtO usage >=10 tpy.

  Table 23--Summary of Standards After Taking Actions Pursuant to CAA Sections 112(d)(2), 112(d)(3), 112(d)(5),
                                                  and 112(f)(2)
----------------------------------------------------------------------------------------------------------------
         Emission source           Existing or new?         EtO use            Standards          CAA section
----------------------------------------------------------------------------------------------------------------
SCV.............................  Existing..........  At least 40 tpy...  99.94 percent       112(f)(2).
                                                                           emission
                                                                           reduction.
                                                      At least 10 tpy     99.94 percent       112(f)(2).
                                                       but less than 40    emission
                                                       tpy.                reduction.
                                                      At least 1 but      99.8 percent        112(f)(2).
                                                       less than 10 tpy.   emission
                                                                           reduction.
                                                      Less than 1 tpy...  99 percent          112(d)(5).
                                                                           emission
                                                                           reduction.
                                  New...............  At least 40 tpy...  99.94 percent       112(f)(2).
                                                                           emission
                                                                           reduction.
                                                      At least 10 tpy     99.94 percent       112(f)(2).
                                                       but less than 40    emission
                                                       tpy.                reduction.
                                                      At least 1 but      99.8 percent        112(f)(2).
                                                       less than 10 tpy.   emission
                                                                           reduction.
                                                      Less than 1 tpy...  99 percent          112(d)(5).
                                                                           emission
                                                                           reduction.
ARV.............................  Existing..........  At least 10 tpy...  99 percent          112(f)(2).
                                                                           emission
                                                                           reduction.
                                                      At least 1 but      99 percent          112(d)(5).
                                                       less than 10 tpy.   emission
                                                                           reduction.
                                                      Less than 1 tpy...  99 percent          112(d)(5).
                                                                           emission
                                                                           reduction.
                                  New...............  At least 10 tpy...  99 percent          112(f)(2).
                                                                           emission
                                                                           reduction.
                                                      At least 1 but      99 percent          112(d)(5).
                                                       less than 10 tpy.   emission
                                                                           reduction.
                                                      Less than 1 tpy...  99 percent
                                                                           emission
                                                                           reduction.
CEV.............................  Existing..........  At least 10 tpy...  3.2E-4 lb/hr......  112(d)(2) and (3).
                                                      At least 1 but      99 percent          112(d)(5).
                                                       less than 10 tpy.   emission
                                                                           reduction.
                                                      Less than 1 tpy...  99 percent          112(d)(5).
                                                                           emission
                                                                           reduction.
                                  New...............  At least 10 tpy...  3.2E-4 lb/hr......  112(d)(2) and (3).
                                                      At least 1 but      99 percent          112(d)(5).
                                                       less than 10 tpy.   emission
                                                                           reduction.
                                                      Less than 1 tpy...  99 percent          112(d)(5).
                                                                           emission
                                                                           reduction.
Group 1 room air emissions at     Existing and new..  N/A...............  1.3E-3 lb/hr \1\..  112(d)(2) and (3).
 major sources.
Group 1 room air emissions at     Existing and new..  N/A...............  1.3E-3 lb/hr \1\..  112(d)(5).
 area sources.
Group 2 room air emissions at     Existing and new..  N/A...............  2.8E-3 lb/hr \1\..  112(d)(2) and (3).
 major sources.
Group 2 room air emissions at     Existing..........  At least 20 tpy...  2.8E-3 lb/hr \1\    112(f)(2).
 area sources.                                                             \2\.
                                                      Less than 20 tpy..  Follow either the   112(d)(5).
                                                                           Cycle Calculation
                                                                           Approach or the
                                                                           Bioburden/
                                                                           Biological
                                                                           Indicator
                                                                           Approach to
                                                                           achieve sterility
                                                                           assurance in
                                                                           accordance with
                                                                           ISO 11135:2014
                                                                           (July 15, 2014)
                                                                           and ISO 11138-
                                                                           1:2017 (March
                                                                           2017) \3\.
                                  New...............  N/A...............  2.8E-3 lb/hr \1\..  112(d)(5).
----------------------------------------------------------------------------------------------------------------
\1\ We are also proposing to require each facility to operate areas with these emissions in accordance with the
  PTE requirements of EPA Method 204 of appendix M to 40 CFR part 51.

[[Page 22832]]

 
\2\ Facilities where MIR is greater than 100-in-1 million after implementation of Control Option 1 must instead
  limit the total volumetric flow rate of exhaust streams that contain Group 2 room air emissions to a maximum
  of 2,900 dscfm at each facility, and the EtO concentration of these streams must not exceed 30 ppbv.
\3\ Owners and operators may also apply for an alternative means of emission limitation under CAA section
  112(h)(3).

E. What environmental justice analysis did we conduct?

    Consistent with the EPA's commitment to integrating EJ in the 
Agency's actions, and following the directives set forth in multiple 
Executive orders, the Agency has carefully considered the impacts of 
this action on communities with EJ concerns. Overall, the results of 
the proximity demographic analysis (see first three columns of Table 
24) indicate that the percent of the population living within 10 km of 
the 97 facilities that is Hispanic or Latino is substantially higher 
than the national average (34 percent versus 19 percent), driven 
largely by the seven facilities in Puerto Rico. The baseline proximity 
analysis indicates that the proportion of other demographic groups 
living within 10 km of commercial sterilizers is closer to the national 
average. The baseline risk-based demographic analysis (see ``baseline'' 
column in Tables 24 to 26), which focuses on those specific locations 
that are expected to have higher cancer risks (greater than or equal to 
1-in-1 million, greater than or equal to 50-in-1 million, and greater 
than 100-in-1 million), suggests that African Americans are 
disproportionally represented at the higher risk levels. The post-
control risk-based demographic analysis focuses on how the options 
considered in this proposed regulatory action would affect the 
distribution of risks within the population identified in the baseline. 
The CAA section 112(d)(2), (3), and (5) post-control scenario is shown 
in Tables 24 to 26 and the residual risk post-control options are shown 
in Tables 27 to 29. The post-control options show a substantial 
reduction in the number of individuals at each risk level, as well as a 
significant reduction in the proportion of African Americans that 
experience higher risk levels from facilities in this source category. 
EPA projects that a majority of the individuals that would remain at 
risk after implementation of the proposed standards is Hispanic or 
Latino, driven largely by the facilities in Puerto Rico. These three 
distinct but complementary analyses indicate the potential for EJ 
concerns associated with this source category in the baseline, as well 
as the substantial benefits these proposed standards would have in 
reducing EtO emissions and associated health risks in communities with 
EJ concerns. For more details see the remainder of this section.
    Executive Order 12898 directs EPA to identify the populations of 
concern who are most likely to experience unequal burdens from 
environmental harms, which are specifically minority populations 
(people of color), low-income populations, and indigenous peoples (59 
FR 7629, February 16, 1994). Additionally, Executive Order 13985 is 
intended to advance racial equity and support underserved communities 
through Federal Government actions (86 FR 7009, January 20, 2021). The 
EPA defines EJ as ``the fair treatment and meaningful involvement of 
all people regardless of race, color, national origin, or income, with 
respect to the development, implementation, and enforcement of 
environmental laws, regulations, and policies.'' \50\ The EPA further 
defines fair treatment to mean that ``no group of people should bear a 
disproportionate burden of environmental harms and risks, including 
those resulting from the negative environmental consequences of 
industrial, governmental, and commercial operations or programs and 
policies.'' In recognizing that people of color and low-income 
populations often bear an unequal burden of environmental harms and 
risks, the EPA continues to consider ways of protecting them from 
adverse public health and environmental effects of air pollution. For 
purposes of analyzing regulatory impacts, the EPA relies upon its June 
2016 ``Technical Guidance for Assessing Environmental Justice in 
Regulatory Analysis,'' \51\ which provides recommendations that 
encourage analysts to conduct the highest quality analysis feasible, 
recognizing that data limitations, time, resource constraints, and 
analytical challenges will vary by media and circumstance. The 
Technical Guidance states that a regulatory action may involve 
potential EJ concerns if it could: (1) Create new disproportionate 
impacts on minority populations, low-income populations, and/or 
Indigenous peoples; (2) exacerbate existing disproportionate impacts on 
minority populations, low-income populations, and/or Indigenous 
peoples; or (3) present opportunities to address existing 
disproportionate impacts on minority populations, low-income 
populations, and/or Indigenous peoples through this action under 
development.
---------------------------------------------------------------------------

    \50\ https://www.epa.gov/environmentaljustice.
    \51\ See https://www.epa.gov/environmentaljustice/technical-guidance-assessing-environmental-justice-regulatory-analysis.
---------------------------------------------------------------------------

    For this proposal, the EPA examined the potential for the 97 
facilities that were assessed to pose concerns to EJ communities both 
in the baseline and under the control options considered in this 
proposal. Specifically, the EPA analyzed how demographics and risk are 
distributed both pre- and post-control, enabling us to address the core 
questions that are posed in the EPA's 2016 Technical Guidance for 
Assessing Environmental Justice in Regulatory Analysis. In conducting 
this analysis, we considered key variables highlighted in the guidance 
including ``minority populations (people of color and Hispanic or 
Latino), low-income populations, and/or indigenous peoples''. The 
methodology and detailed results of the demographic analysis are 
presented in a technical report, Analysis of Demographic Factors for 
Populations Living Near Ethylene Oxide Commercial Sterilization and 
Fumigation Operations, available in the docket for this action.
    To examine the potential for EJ concerns in the pre-control 
baseline, the EPA conducted two baseline demographic analyses, a 
proximity analysis and a risk-based analysis. The baseline proximity 
demographic analysis is an assessment of individual demographic groups 
in the total population living within 10 kilometers (km) and 50 km of 
the facilities. In this preamble, we focus on the 10 km radius for the 
demographic analysis because it encompasses all the facility MIR 
locations and captures 100 percent of the population with risks greater 
than 100-in-1 million. The results of the proximity analysis for 
populations living within 50 km are included in the technical report 
included in the docket for this proposed rule.
    The baseline risk-based demographic analysis is an assessment of 
risks to individual demographic groups in the population living within 
the 10 km and 50 km radii around the facilities prior to the 
implementation of any controls proposed by this action (``baseline''). 
Again, in this preamble, we focus on the results for populations living 
within 10 km of facilities. Results for populations living within 50 km 
are included in the technical report included in the docket for this 
proposed rule.

[[Page 22833]]

1. Demographics
    The first three columns of Tables 24, 25, and 26 of this document 
show the total population, population percentages, and population count 
for each demographic group for the nationwide population and the total 
population living within 10 km of EtO sterilization facilities. A total 
of 19.4 million people live within 10 km of the 97 facilities that were 
assessed. The results of the proximity demographic analysis indicate 
that the percent of the population that is Hispanic or Latino is 
substantially higher than the national average (34 percent versus 19 
percent), driven by the seven facilities in Puerto Rico, where an 
average of 99 percent of the 658,000 people living within 10 km of the 
facilities are Hispanic or Latino. The percent of the population that 
is ``Other and multiracial'' (13 percent) is higher than the national 
average (8 percent). The percentages of the population that are African 
American (13 percent) or Native American (0.3 percent) are similar to 
or less than the national averages (12 percent and 0.7 percent, 
respectively). The percent of people living below the poverty level (14 
percent) and those over the age of 25 without a high school diploma (15 
percent) are higher than the national averages (13 percent and 12 
percent, respectively). The percent of people living in linguistic 
isolation is double the national average (10 percent versus 5 
percent).\52\ However, we note that this estimate of linguistic 
isolation is largely driven by the facilities in Puerto Rico, where an 
average of 67 percent of the population is in linguistic isolation in 
comparison to the national average.
---------------------------------------------------------------------------

    \52\ Linguistic Isolation is defined in the U.S. Census Bureau's 
American Community Survey as ``a household in which all members age 
14 years and over speak a non-English language and also speak 
English less than ``very well'' (have difficulty with English).''
---------------------------------------------------------------------------

    In summary, the baseline proximity analysis indicates that the 
percent of Hispanic or Latino populations living near commercial 
sterilizers (within 10 km) is higher than what would be expected based 
on the national average distribution. This is largely driven by the 
seven facilities located in Puerto Rico where, on average, the 
population of 658,000 people living within 10 km of these seven 
facilities is 99 percent Hispanic or Latino. In addition, the 
population around the facilities in Puerto Rico has 67 percent living 
in linguistic isolation, 45 percent living below the poverty level, and 
24 percent over 25 without a high school diploma.
2. Baseline Risk-Based Demographics
    The baseline risk-based demographic analysis results are shown in 
the ``baseline'' column of Tables 24, 25, and 26. This analysis focused 
on the populations living within 10 km of the facilities with estimated 
cancer risks greater than or equal to 1-in-1 million (Table 24), 
greater than or equal to 50-in-1 million (Table 25), and greater than 
100-in-1 million (Table 26). The risk analysis indicated that emissions 
from the source category, prior to the reductions we are proposing, 
expose a total of 5.3 million people to a cancer risk greater than or 
equal to 1-in-1 million around 78 facilities, 119,000 people to a 
cancer risk greater than or equal to 50-in-1 million around 42 
facilities, and 18,000 people to a cancer risk greater than 100-in-1 
million around 16 facilities. The demographics of the baseline 
population with estimated cancer risks greater than or equal to 1-in-1 
million are very similar to the total population within 10 km. 
Specifically, the percent of the population that is Hispanic or Latino 
is significantly above the national average (38 percent versus 19 
percent), the percent below the poverty level is above national average 
(16 percent versus 13 percent), the percent over 25 without a high 
school diploma is above the national average (18 percent versus 12 
percent), and the percent linguistic isolation is two times the 
national average (11 percent versus 5 percent). In contrast, the 
smaller populations with baseline cancer risk greater than or equal to 
50-in-1 million (119,000 people) and >100-in-1 million (18,000 people) 
are predominantly made up of African Americans (45 and 34 percent 
versus 12 percent nationally), have a higher percentage of the 
population below the poverty level (22 and 23 percent versus 13 percent 
nationally), the percent over 25 without a high school diploma is above 
the national average (17 and 16 percent versus 12 percent) and 
linguistic isolation is above the national average (7 and 10 percent 
versus 5 percent). This shows that risks tend to be higher where more 
African American residents reside and where poverty is higher than in 
the rest of the area within 10 km. It should be noted that, the higher 
percentage African American population with baseline cancer risk 
greater than or equal to 50-in-1 million is driven largely by seven 
facilities that have African American populations that are between two 
and eight times the national average. The higher percentage African 
American population with baseline cancer risk greater than 100-in-1 
million is driven largely by three facilities that are located in 
communities where the proportion of African American residents is 
between 2.5 and 8 times the national average. The population with 
higher baseline cancer risks living within 10 km of the facilities 
consists of a substantially smaller percentage of Hispanic or Latino 
(18 and 19 percent) than the total population living within 10 km (34 
percent Hispanic or Latino) and is near the national average (19 
percent).
    In summary, the baseline risk-based demographic analysis, which 
focuses on those specific locations that are expected to have higher 
cancer risks, suggests that African Americans are the one demographic 
group disproportionally represented where risk is highest. The 
population with risks greater than 100-in-1 million living within 10 km 
of a commercial sterilizer has a significantly higher proportion of 
African Americans (34 percent) than the national average (12 percent).
3. Risk-Based Demographics Considering Standards Under CAA Sections 
112(d)(2), (3), and (5)
    This analysis focused on the populations living within 10 km of the 
facilities with estimated cancer risks greater than or equal to 1-in-1 
million (Table 24), greater than or equal to 50-in-1 million (Table 
25), and greater than 100-in-1 million (Table 26) after implementation 
of standards that we are proposing under CAA sections 112(d)(2), (3), 
and (5). The results of our analysis of risk-based demographics 
considering standards under CAA sections 112(d)(2), (3), and (5) are 
shown in the last column of Tables 24, 25, and 26 titled ``Baseline and 
CAA Section 112(d)(2), (3), and (5).'' In this analysis we evaluated 
how the proposed CAA sections 112(d)(2), (3), and (5) emission 
reductions in this proposed regulatory action affect the distribution 
of risks identified in the baseline. This enables us to characterize 
the post-control risks and to evaluate whether the proposed action 
creates or mitigates potential EJ concerns as compared to the baseline. 
Note that as described in section III.C, the risk results in this 
scenario were based on requiring BMP (Option 2) under section 112(d)(5) 
for Group 1 room air emissions, instead of the proposed emission limit 
reflecting use of control devices (Option 1). Therefore, the 
populations at the various risk levels may be lower than reported here 
(and the demographics slightly different).
    The risk analysis indicated that the emissions from the source 
category, after implementation of the emissions reductions we are 
proposing under CAA

[[Page 22834]]

section 112(d), reduces the number of people living within 10 km of a 
facility and with a cancer risk greater than or equal to 1-in-1 million 
from 5.3 million people around 78 facilities to 2.6 million people 
around 73 facilities, reduces the number of people living within 10 km 
of a facility and with a cancer risk greater than or equal to 50-in-1 
million from 119,000 people around 42 facilities to 19,000 people 
around 20 facilities, and reduces the number of people living within 10 
km of a facility and with a cancer risk greater than 100-in-1 million 
from 18,000 people around 16 facilities to 2,350 people around 13 
facilities.
    The demographics of the population with estimated cancer risks 
greater than or equal to 1-in-1 million considering the standards we 
are proposing under CAA section 112(d) are very similar to both the 
total population within 10 km and to the baseline population with risks 
greater than or equal to 1-in-1 million. Specifically, the percent of 
the population that is Hispanic or Latino is significantly above the 
national average (32 percent versus 19 percent), the percent below the 
poverty level is above national average (16 percent versus 13 percent), 
the percent over 25 without a high school diploma is above the national 
average (16 percent versus 12 percent), and the percent linguistic 
isolation is two times the national average (10 percent versus 5 
percent).
    After implementation of the standards we are proposing under CAA 
section 112(d), the percentage and number of African Americans at 
cancer risks greater than or equal to 50-in-1 million and greater than 
100-in-1 million is significantly reduced. For example, African 
Americans exposed to risks greater than 100-in-1 million went from 34 
percent or 6,000 people in the baseline to 11 percent or 300 people 
after implementation of the proposed technology review emissions 
reductions. It should be noted that, the percentage of the population 
that is Hispanic or Latino exposed to risks greater than 100-in-1 
million went up from 18 percent in the baseline to 51 percent after the 
proposed technology review emissions reductions. However, the number of 
Hispanic or Latino people with risks greater than 100-in-1 million was 
reduced from 3,000 to 1,200 people. Similarly, the percentage of the 
population that are below the poverty level or are linguistically 
isolated with a cancer risk greater than 100-in-1 million went up from 
the baseline, but the number of people in these demographics decreased 
significantly. For example, the proportion of the population with risks 
greater than 100-in-1 million that were below the poverty level was 
much higher than the baseline (34 percent versus 23 percent), but the 
number of people was reduced from 4,000 people to 800 people.
    In summary, the proposed CAA section 112(d) standards significantly 
reduced the number of people in all demographic groups that are exposed 
to risks greater than or equal to 1-in-1 million, greater than and 
equal to 50-in-1 million, and greater than 100-in-1 million. 
Specifically, the percent of the population that is African American 
who are at a cancer risk greater than or equal to 50-in-1 million and 
greater than 100-in-1 million was reduced from about 40 percent in the 
baseline to about 15 percent after the technology review controls. The 
percentage of Hispanic or Latino people increased as the higher risk 
facilities in Puerto Rico make-up an increasing portion of the 
remaining populations with higher cancer risks.

      Table 24--Comparison of Baseline and CAA Section 112(d)(2), (3), and (5) Post-Control Demographics of
Populations With Cancer Risk Greater Than or Equal to 1-in-1 Million Living Within 10 km of Facilities That Were
                                                    Assessed
----------------------------------------------------------------------------------------------------------------
                                                                       Total       Cancer risk >=1-in-1 million
                                                                    population   -------------------------------
                Demographic group                   Nationwide     living within
                                                                   10 km of EtO      Baseline      Post-control
                                                                    facilities
----------------------------------------------------------------------------------------------------------------
Total Population................................            328M           19.4M            5.3M        \1\ 2.6M
Number of Facilities............................  ..............              97              78          \1\ 73
----------------------------------------------------------------------------------------------------------------
                                Race and Ethnicity by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
White...........................................       60 [197M]       40 [7.7M]       40 [2.1M]     \1\ 43 [1M]
African American................................        12 [40M]       13 [2.5M]       15 [780K]   \1\ 19 [480K]
Native American.................................        0.7 [2M]       0.3 [56K]       0.3 [16K]    \1\ 0.3 [7K]
Hispanic or Latino (includes white and nonwhite)        19 [62M]       34 [6.5M]         38 [2M]   \1\ 32 [840K]
Other and Multiracial...........................         8 [27M]       13 [2.6M]        7 [360K]    \1\ 6 [150K]
----------------------------------------------------------------------------------------------------------------
                                      Income by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Below Poverty Level.............................        13 [44M]       14 [2.8M]       16 [800K]   \1\ 16 [400K]
Above Poverty Level.............................       87 [284M]      86 [16.6M]       84 [4.5M]   \1\ 84 [2.2M]
----------------------------------------------------------------------------------------------------------------
                                     Education by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Over 25 and without a High School Diploma.......        12 [40M]         15 [3M]       18 [900K]   \1\ 16 [400K]
Over 25 and with a High School Diploma..........       88 [288M]      85 [16.4M]       82 [4.4M]   \1\ 84 [2.2M]
----------------------------------------------------------------------------------------------------------------
                              Linguistically Isolated by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Linguistically Isolated.........................         5 [18M]         10 [2M]       11 [600K]   \1\ 10 [300K]
----------------------------------------------------------------------------------------------------------------
\1\ These values may be lower because the proposed Group 1 room air emission standards were not applied or
  accounted for in the risk assessment.
Notes:
 Nationwide population and demographic percentages are based on the Census Bureau's (Census) 2015-2019
  American Community Survey (ACS) 5-year block group averages. Total population count within 10 km is based on
  2010 Decennial Census block population.

[[Page 22835]]

 
 To avoid double counting, the ``Hispanic or Latino'' category is treated as a distinct demographic
  category. A person who identifies as Hispanic or Latino is counted as Hispanic or Latino, regardless of race.
 The number of facilities represents facilities with a cancer MIR above level indicated. When the MIR
  was located at a user assigned receptor at an individual residence and not at a census block centroid, we were
  unable to estimate population and demographics for that facility.
 The sum of individual populations with a demographic category may not add up to total due to rounding.


      Table 25--Comparison of Baseline and CAA Section 112(d)(2), (3), and (5) Post-Control Demographics of
  Populations With Cancer Risk Greater Than or Equal to 50-in-1 Million Living Within 10 km of Facilities That
                                                  Were Assessed
----------------------------------------------------------------------------------------------------------------
                                                                       Total       Cancer risk >=50-in-1 million
                                                                    population   -------------------------------
                Demographic group                   Nationwide     living within
                                                                   10 km of EtO      Baseline      Post-control
                                                                    facilities
----------------------------------------------------------------------------------------------------------------
Total Population................................            328M           19.4M         119,000      \1\ 19,000
Number of Facilities............................  ..............              97              42          \1\ 20
----------------------------------------------------------------------------------------------------------------
                                Race and Ethnicity by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
White...........................................       60 [197M]       40 [7.7M]        33 [39K]    \1\ 54 [10K]
African American................................        12 [40M]       13 [2.5M]        45 [54K]     \1\ 19 [4K]
Native American.................................        0.7 [2M]       0.3 [56K]       0.1 [200]  \1\ 0.1 [<100]
Hispanic or Latino (includes white and nonwhite)        19 [62M]       34 [6.5M]        19 [23K]     \1\ 25 [5K]
Other and Multiracial...........................         8 [27M]       13 [2.6M]          3 [4K]     \1\ 2 [400]
----------------------------------------------------------------------------------------------------------------
                                      Income by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Below Poverty Level.............................        13 [44M]       14 [2.8M]        22 [26K]     \1\ 23 [4K]
Above Poverty Level.............................       87 [284M]      86 [16.6M]        78 [93K]    \1\ 77 [15K]
----------------------------------------------------------------------------------------------------------------
                                     Education by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Over 25 and without a High School Diploma.......        12 [40M]         15 [3M]         17 [8K]     \1\ 15 [2K]
Over 25 and with a High School Diploma..........       88 [288M]      85 [16.4M]       83 [111K]    \1\ 85 [17K]
----------------------------------------------------------------------------------------------------------------
                              Linguistically Isolated by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Linguistically Isolated.........................         5 [18M]         10 [2M]         7 [54K]     \1\ 13 [4K]
----------------------------------------------------------------------------------------------------------------
\1\These values may be lower because the proposed Group 1 room air emission standards were not applied or
  accounted for in the risk assessment.
Notes:
 Nationwide population and demographic percentages are based on Census' 2015-2019 ACS 5-year block group
  averages. Total population count within 10 km is based on 2010 Decennial Census block population.
 To avoid double counting, the ``Hispanic or Latino'' category is treated as a distinct demographic
  category. A person who identifies as Hispanic or Latino is counted as Hispanic or Latino, regardless of race.
 The number of facilities represents facilities with a cancer MIR above level indicated. When the MIR
  was located at a user assigned receptor at an individual residence and not at a census block centroid, we were
  unable to estimate population and demographics for that facility.
 The sum of individual populations with a demographic category may not add up to total due to rounding.
 To account for the uncertainty of demographics estimates in smaller populations, any population values
  of 100 persons or less have been shown simply as ``<100.''


      Table 26--Comparison of Baseline and CAA Section 112(d)(2), (3), and (5) Post-Control Demographics of
 Populations With Cancer Risk Greater Than 100-in-1 Million Living Within 10 km of Facilities That Were Assessed
----------------------------------------------------------------------------------------------------------------
                                                                       Total      Cancer risk >=100-in-1 million
                                                                    population   -------------------------------
                Demographic group                   Nationwide     living within
                                                                   10 km of EtO      Baseline      Post-control
                                                                    facilities
----------------------------------------------------------------------------------------------------------------
Total Population................................            328M           19.4M          18,000       \1\ 2,350
Number of Facilities............................  ..............              97              16          \1\ 13
----------------------------------------------------------------------------------------------------------------
                                Race and Ethnicity by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
White...........................................       60 [197M]       40 [7.7M]         45 [8K]    \1\ 37 [900]
African American................................        12 [40M]       13 [2.5M]         34 [6K]    \1\ 11 [300]
Native American.................................        0.7 [2M]       0.3 [56K]      0.1 [<100]           0 [0]
Hispanic or Latino (includes white and nonwhite)        19 [62M]       34 [6.5M]         18 [3K]   \1\ 51 [1.2K]
Other and Multiracial...........................         8 [27M]       13 [2.6M]         3 [500]    \1\ 1 [<100]
----------------------------------------------------------------------------------------------------------------

[[Page 22836]]

 
                                      Income by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Below Poverty Level.............................        13 [44M]       14 [2.8M]         23 [4K]    \1\ 34 [800]
Above Poverty Level.............................       87 [284M]      86 [16.6M]        77 [14K]  \1\ 66 [1.55K]
----------------------------------------------------------------------------------------------------------------
                                     Education by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Over 25 and without a High School Diploma.......        12 [40M]         15 [3M]         16 [2K]    \1\ 17 [700]
Over 25 and with a High School Diploma..........       88 [288M]      85 [16.4M]        84 [15K]  \1\ 83 [1.65K]
----------------------------------------------------------------------------------------------------------------
                              Linguistically Isolated by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Linguistically Isolated.........................         5 [18M]         10 [2M]         10 [6K]    \1\ 31 [300]
----------------------------------------------------------------------------------------------------------------
\1\ These values may be lower because the proposed Group 1 room air emission standards were not applied or
  accounted for in the risk assessment.
Notes:
 Nationwide population and demographic percentages are based on Census' 2015-2019 ACS 5-year block group
  averages. Total population count within 10 km is based on 2010 Decennial Census block population.
 To avoid double counting, the ``Hispanic or Latino'' category is treated as a distinct demographic
  category. A person who identifies as Hispanic or Latino is counted as Hispanic or Latino, regardless of race.
 The number of facilities represents facilities with a cancer MIR above level indicated. When the MIR
  was located at a user assigned receptor at an individual residence and not at a census block centroid, we were
  unable to estimate population and demographics for that facility.
 The sum of individual populations with a demographic category may not add up to total due to rounding.
 To account for the uncertainty of demographics estimates in smaller populations, any population values
  of 100 persons or less have been shown simply as ``<100.''

4. Residual Risk Post-Control Risk-Based Demographics
    This analysis focused on the populations living within 10 km of the 
facilities with estimated cancer risks greater than or equal to 1-in-1 
million (Table 27), greater than or equal to 50-in-1 million (Table 
28), and greater than 100-in-1 million (Table 29) after implementation 
of the control options investigated under the residual risks analysis 
as described in section III.D of this preamble. The demographic results 
for the control options are in the columns titled ``Control Option 1'' 
and ``Control Option 2.'' One of these control options would be 
implemented in addition to the CAA section 112(d)(2), (3), and (5) 
post-control emissions reductions. Therefore, in this analysis, we 
evaluated how all of the proposed controls and emission reductions 
described in this action affect the distribution of risks. This enables 
us to characterize the post-control risks and to evaluate whether the 
proposed action creates or mitigates potential EJ concerns as compared 
to the baseline. Again, as described in section III.C, the risk results 
in this scenario were based on requiring BMP (Option 2) under section 
112(d)(5) for Group 1 room air emissions, instead of the proposed 
emission limit reflecting use of control devices (Option 1). Therefore, 
the populations at the various risk levels may be lower than reported 
here (and the demographics slightly different).
    The risk analysis indicated that the number of people exposed to 
risks greater than or equal to 1-in-1 million within 10 km of a 
facility (Table 27) is reduced from 2.6 million people after 
implementation of the CAA section 112(d)(2), (3), and (5) controls to 
approximately 1.15 million people after implementation of one of the 
residual risk control options. This represents a significant reduction 
(about 60 percent reduction) in the size of the populations at risk for 
each of the three residual risk control options investigated when 
compared to the populations after implementation of the technology 
review controls. The populations with a cancer risk greater than or 
equal to 1-in-1 million are located around 73 facilities for both post-
control options.
    The demographics of the post-control population living within 10 km 
of a facility and with an estimated cancer risks greater than or equal 
to 1-in-1 million for control options 1 and 2 (Table 27) are very 
similar to the CAA section 112(d)(2), (3), and (5) post-control 
population with risks greater than or equal to 1-in-1 million. 
Specifically, the percent of the population that is Hispanic or Latino 
is significantly above the national average (37 percent versus 19 
percent), the percent below poverty is above national average (16 
percent versus 13 percent), the percent over 25 without a high school 
diploma is above the national average (16 percent versus 12 percent), 
and the percent linguistic isolation is almost two times the national 
average (9 percent versus 5 percent).
    The risk analysis indicated that the number of people living within 
10 km of a facility and exposed to risks greater than or equal to 50-
in-1 million (Table 28) is reduced from 19,000 people after 
implementation of the CAA section 112(d)(2), (3), and (5) controls to 
1,400 to 2,000 people after implementation of one of the residual risk 
control options. This represents a 90 percent reduction in the size of 
the populations at risk for each of the three residual risk control 
options investigated when compared to the populations after 
implementation of the CAA section 112(d)(2), (3), and (5) controls. The 
populations living within 10 km of a facility and with a cancer risk 
greater than or equal to 50-in-1 million are located around 11 
facilities for both post-control options.
    The demographics of the post-control population living within 10 km 
of a facility and with estimated cancer risks greater than or equal to 
50-in-1 million for control options 1 and 2 (Table 28)

[[Page 22837]]

are significantly different from the population after implementation of 
the CAA section 112(d)(2), (3), and (5) controls. Specifically, the 
percent of the population that is Hispanic or Latino is significantly 
higher at 79 percent and 72 percent for control options 1 and 2, 
respectively. This higher percentage is driven by three facilities in 
Puerto Rico and one in Texas, for which the population is over 95 
percent Hispanic or Latino. However, the number of Hispanic or Latino 
people with risks greater than or equal to 50-in-1 million was reduced 
by about 80 percent from 5,000 people to 1,600 and 1,000 people for 
Option 1 and 2, respectively. Similarly, the percentage of the 
population that is below the poverty level or linguistically isolated 
went up from the CAA section 112(d)(2), (3), and (5) post-control 
population, but the number of people in these demographics decreased 
significantly.
    The risk analysis indicated that the number of people living with 
10 km of a facility and exposed to risks greater than 100-in-1 million 
(Table 29) is reduced from 2,350 people after implementation of the CAA 
section 112(d)(2), (3), and (5) controls to 33 people for Option 1 and 
to zero people for Option 2. For control Option 1, there are three 
facilities with risks greater than 100-in-1 million. Two of these 
facilities are located in Puerto Rico and one is in Utah.\53\ The 
demographics in Table 29 are for one of the facilities in Puerto Rico. 
For the other two facilities, the MIR was located at individual 
residences closest to the facilities and not at a census block 
centroid. Therefore, we were unable to estimate the risk-based 
population and risk-based demographics for those facilities. However, 
the proximity analysis indicated that the demographics for all people 
living within 10 km of the other Puerto Rico facility are almost 
identical to the one shown in Table 29. The proximity analysis shows 
that the population of all people living within 10 km of the Utah 
facility is 80 percent white with the percent Hispanic or Latino, 
African American, below the poverty level, over 25 without a high 
school education, and linguistic isolation all below the national 
average.
---------------------------------------------------------------------------

    \53\ As described in section III.D.1.c, we expect the risks at 
one of the facilities in Puerto Rico to be below 100-in-1 million 
after accounting for the proposed Group 1 room air emission 
reductions.
---------------------------------------------------------------------------

    For control Option 2, there are no facilities or people with risks 
greater than 100-in-1 million. Therefore, there are no greater than 
100-in-1 million demographics to discuss.
    In summary, as shown in the residual risk post-control risk-based 
demographic analysis, the options under consideration in this proposal 
would reduce the number of people and facilities expected to have 
cancer risks greater than or equal to 1-in-1 million, greater than or 
equal to 50-in-1 million, and greater than 100-in-1 million 
significantly. Under Option 1, the percentage of population that is 
Hispanic or Latino, below the poverty level, over 25 without a high 
school diploma, and in linguistic isolation increases as the cancer 
risk increases. This trend is driven largely by the higher risk 
facilities in Puerto Rico. Under Option 1, the number of Hispanic or 
Latino people that are exposed to risks greater than or equal to 1-in-1 
million is reduced by 50 percent, the number of Hispanic or Latino 
people that are exposed to risks greater than or equal to 50-in-1 
million is reduced by 70 percent, and the number of Hispanic or Latino 
people that are exposed to risks greater than 100-in-1 million is 
reduced by 97 percent. The three facilities remaining above 100-in-1 
million for Option 1 are located in Puerto Rico (two facilities) and 
Utah. The two facilities in Puerto Rico have Hispanic or Latino 
populations of greater than 99 percent and the population around the 
facility in Utah is 80 percent white.
    Under Option 2, the number of Hispanic or Latino people that are 
exposed to risks greater than or equal to 1-in-1 million is reduced by 
50 percent, the number of Hispanic or Latino people that are exposed to 
risks greater than or equal to 50-in-1 million is reduced by 80 
percent, and the number of Hispanic or Latino people that are exposed 
to risks greater than 100-in-1 million is reduced by 100 percent. We 
note that, primarily driven by the higher risk facilities in Puerto 
Rico, the percentage of population that is Hispanic or Latino, below 
the poverty level, over 25 without a high school diploma, and in 
linguistic isolation increases as the cancer risk increases from 
greater than or equal to 1-in-1 million to greater than 50-in-1 
million. Under Option 2, there are no facilities or people with risks 
greater than 100-in-1 million.

Table 27--Comparison of Post-Control Demographics for Populations With Cancer Risk Greater Than or Equal to 1-in-
               1 Million Living Within 10 km of Sterilizer Facilities for Various Control Options
----------------------------------------------------------------------------------------------------------------
                                                                     Cancer risk >=1-in-1 million
                                                     -----------------------------------------------------------
        Demographic group             Nationwide       Post-control CAA
                                                      section 112(d)(2),   Control option 1    Control option 2
                                                         (3), and (5)
----------------------------------------------------------------------------------------------------------------
Total Population................  328M..............  2.6M \1\..........  1.2M \1\..........  1.1M \1\
Number of Facilities with Pop.                        73 \1\............  73 \1\............  73 \1\
 Above Cancer Level.
----------------------------------------------------------------------------------------------------------------
                                Race and Ethnicity by Percent [number of people]
----------------------------------------------------------------------------------------------------------------
White...........................  60 percent [197M].  43 percent [1M]     38 percent [447K]   38 percent [429K]
                                                       \1\.                \1\.                \1\
African American................  12 percent [40M]..  19 percent [480K]   18 percent [209K]   18 percent [208K]
                                                       \1\.                \1\.                \1\
Native American.................  0.7 percent [2M]..  0.3 percent [7K]    0.4 percent [5K]    0.4 percent [4.5K]
                                                       \1\.                \1\.                \1\
Hispanic or Latino (includes      19 percent [62M]..  32 percent [840K]   37 percent [431K]   37 percent [419K]
 white and nonwhite).                                  \1\.                \1\.                \1\
Other and Multiracial...........  8 percent [27M]...  6 percent [150K]    7 percent [76K]     7 percent [74K]
                                                       \1\.                \1\.                \1\
----------------------------------------------------------------------------------------------------------------
                                      Income by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Below Poverty Level.............  13 percent [44M]..  16 percent [400K]   16 percent [182K]   16 percent [177K]
                                                       \1\.                \1\.                \1\
Above Poverty Level.............  87 percent [284M].  84 percent [2.2M]   84 percent [1M]     84 percent [900K]
                                                       \1\.                \1\.                \1\

[[Page 22838]]

 
                                     Education by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
> 25 w/o a HS Diploma...........  12 percent [40M]..  16 percent [400K]   16 percent [186K]   16 percent [181K]
                                                       \1\.                \1\.                \1\
> 25 w/HS Diploma...............  88 percent [288M].  84 percent [2.2M]   84 percent [1M]     84 percent [900K]
                                                       \1\.                \1\.                \1\
----------------------------------------------------------------------------------------------------------------
                              Linguistically Isolated by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Linguistically Isolated.........  5 percent [18M]...  10 percent [300K]   9 percent [105K]    9 percent [100K]
                                                       \1\.                \1\.                \1\
----------------------------------------------------------------------------------------------------------------
\1\ These values may be lower because the proposed Group 1 room air emission standards were not applied or
  accounted for in the risk assessment
Notes:
 Nationwide population and demographic percentages are based on Census' 2015-2019 ACS 5-year block group
  averages. Total population count within 10 km is based on 2010 Decennial Census block population.
 To avoid double counting, the ``Hispanic or Latino'' category is treated as a distinct demographic
  category. A person who identifies as Hispanic or Latino is counted as Hispanic or Latino, regardless of race.
 The number of facilities represents facilities with a cancer MIR above level indicated. When the MIR
  was located at a user assigned receptor at an individual residence and not at a census block centroid, we were
  unable to estimate population and demographics for that facility.
 The sum of individual populations with a demographic category may not add up to total due to rounding.


 Table 28--Comparison of Post-Control Demographics for Populations With Cancer Risk Greater Than or Equal to 50-
              in-1 Million Living Within 10 km of Sterilizer Facilities for Various Control Options
----------------------------------------------------------------------------------------------------------------
                                                                    Cancer risk >= 50-in-1 million
                                                     -----------------------------------------------------------
                                                          CAA section
        Demographic group             Nationwide        112(d)(2), (3),
                                                         and (5) post-     Control option 1    Control option 2
                                                            control
----------------------------------------------------------------------------------------------------------------
Total Population................  328M..............  19,000 \1\........  1,985 \1\.........  1,368 \1\
Number of Facilities with Pop.                        20 \1\............  11 \1\............  11 \1\
 Above Cancer Level.
----------------------------------------------------------------------------------------------------------------
                                Race and Ethnicity by Percent [number of people]
----------------------------------------------------------------------------------------------------------------
White...........................  60 percent [197M].  54 percent [10K]    12 percent [200]    15 percent [200]
                                                       \1\.                \1\.                \1\
African American................  12 percent [40M]..  19 percent [4K]     7 percent [100]     10 percent [100]
                                                       \1\.                \1\.                \1\
Native American.................  0.7 percent [2M]..  0.1 percent [<100]  0.2 percent [<100]  0.3 percent [<100]
                                                       \1\.                \1\.                \1\
Hispanic or Latino (includes      19 percent [62M]..  25 percent [5K]     79 percent [1,600]  72 percent [1000]
 white and nonwhite).                                  \1\.                \1\.                \1\
Other and Multiracial...........  8 percent [27M]...  2 percent [400]     2 percent [<100]    3 percent [<100]
                                                       \1\.                \1\.                \1\
----------------------------------------------------------------------------------------------------------------
                                      Income by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Below Poverty Level.............  13 percent [44M]..  23 percent [4K]     35 percent [700]    26 percent [400]
                                                       \1\.                \1\.                \1\
Above Poverty Level.............  87 percent [284M].  77 percent [15K]    65 percent [1,300]  74 percent [1K]
                                                       \1\.                \1\.                \1\
----------------------------------------------------------------------------------------------------------------
                                     Education by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
> 25 w/o a HS Diploma...........  12 percent [40M]..  15 percent [2K]     20 percent [400]    20 percent [300]
                                                       \1\.                \1\.                \1\
> 25 w/HS Diploma...............  88 percent [288M].  85 percent [17K]    80 percent [1,600]  80 percent [1K]
                                                       \1\.                \1\.                \1\
----------------------------------------------------------------------------------------------------------------
                              Linguistically Isolated by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Linguistically Isolated.........  5 percent [18M]...  13 percent [4K]     34 percent [700]    21 percent [300]
                                                       \1\.                \1\.                \1\
----------------------------------------------------------------------------------------------------------------
\1\ These values may be lower because the proposed Group 1 room air emission standards were not applied or
  accounted for in the risk assessment
Notes:
 Nationwide population and demographic percentages are based on Census' 2015-2019 ACS 5-year block group
  averages. Total population count within 10 km is based on 2010 Decennial Census block population.
 To avoid double counting, the ``Hispanic or Latino'' category is treated as a distinct demographic
  category. A person who identifies as Hispanic or Latino is counted as Hispanic or Latino, regardless of race.
 The number of facilities represents facilities with a cancer MIR above level indicated. When the MIR
  was located at a user assigned receptor at an individual residence and not at a census block centroid, we were
  unable to estimate population and demographics for that facility.
 The sum of individual populations with a demographic category may not add up to total due to rounding.
 To account for the uncertainty of demographics estimates in smaller populations, any population values
  of 100 persons or less have been shown simply as ``<100''.


[[Page 22839]]


Table 29--Comparison of Post-Control Demographics for Populations With Cancer Risk Greater Than 100-in-1 Million
                    Living Within 10 km of Sterilizer Facilities for Various Control Options
----------------------------------------------------------------------------------------------------------------
                                                                           Cancer risk >100-in-1 million
                                                                 -----------------------------------------------
                                                                    CAA section
                Demographic group                   Nationwide      112(d)(2),    Control option  Control option
                                                                   (3), and (5)          1               2
                                                                   post-control
----------------------------------------------------------------------------------------------------------------
Total Population................................            328M       2,350 \1\              33               0
Number of Facilities with Pop. Above Cancer                               13 \1\           3 \1\               0
 Level..........................................
----------------------------------------------------------------------------------------------------------------
                                Race and Ethnicity by Percent [number of people]
----------------------------------------------------------------------------------------------------------------
White...........................................      60 percent      37 percent     0.9 percent
                                                          [197M]       [900] \1\             [0]
African American................................      12 percent      11 percent     0.1 percent
                                                           [40M]       [300] \1\             [0]
Native American.................................     0.7 percent   0 percent [0]   0 percent [0]
                                                            [2M]
Hispanic or Latino (includes white and nonwhite)      19 percent      51 percent      99 percent
                                                           [62M]      [1.2K] \1\          [<100]
Other and Multiracial...........................       8 percent       1 percent     0.1 percent
                                                           [27M]      [<100] \1\             [0]
----------------------------------------------------------------------------------------------------------------
                                      Income by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Below Poverty Level.............................      13 percent      34 percent      61 percent
                                                           [44M]       [800] \1\          [<100]
Above Poverty Level.............................      87 percent      66 percent      39 percent
                                                          [284M]     [1.55K] \1\          [<100]
----------------------------------------------------------------------------------------------------------------
                                     Education by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
> 25 w/o a HS Diploma...........................      12 percent      17 percent      27 percent
                                                           [40M]       [700] \1\          [<100]
> 25 w/HS Diploma...............................      88 percent      83 percent      73 percent
                                                          [288M]     [1.65K] \1\          [<100]
----------------------------------------------------------------------------------------------------------------
                              Linguistically Isolated by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Linguistically Isolated.........................       5 percent      31 percent      84 percent
                                                           [18M]       [300] \1\          [<100]
----------------------------------------------------------------------------------------------------------------
\1\ These values may be lower because the proposed Group 1 room air emission standards were not applied or
  accounted for in the risk assessment
Notes:
 Nationwide population and demographic percentages are based on Census' 2015-2019 ACS 5-year block group
  averages. Total population count within 10 km is based on 2010 Decennial Census block population.
 To avoid double counting, the ``Hispanic or Latino'' category is treated as a distinct demographic
  category. A person who identifies as Hispanic or Latino is counted as Hispanic or Latino, regardless of race.
 The number of facilities represents facilities with a cancer MIR above level indicated. When the MIR
  was located at a user assigned receptor at an individual residence and not at a census block centroid, we were
  unable to estimate population and demographics for that facility.
 The sum of individual populations with a demographic category may not add up to total due to rounding.
 To account for the uncertainty of demographics estimates in smaller populations, any population values
  of 100 persons or less have been shown simply as ``<100''.

F. What are the results and proposed decisions based on our technology 
review, and what is the rationale for those decisions?

1. SCV At Facilities Where EtO Use Is at Least 10 Tpy
    The current subpart O contains emission standards for SCVs at 
facilities where EtO use is at least 10 tpy. There are 47 facilities 
where EtO use is at least 10 tpy, all of which have SCVs. Of these 
facilities, 26 currently use wet scrubbers to control their SCV 
emissions, 11 use catalytic oxidizers, and six use a wet scrubber and 
gas/solid reactor in series, four use thermal oxidizers, and one uses a 
wet scrubber and catalytic oxidizer in series. Performance tests are 
available for SCVs at all facilities where EtO use is at least 10 tpy. 
We reviewed these performance tests, and the reported emission 
reductions ranged from 99.6 percent to 99.999996 percent.
    We considered two potential options as part of the technology 
review. The first option we considered (Option 1) is 99.94 percent 
emission reduction. The second option we considered (Option 2) is the 
maximum SCV emission reduction that all facilities where EtO use is at 
least 10 tpy are currently meeting, which is 99.6 percent. We 
considered these standards as part of the analysis pursuant to CAA 
section 112(f)(2) as discussed in section III.C. Under Option 1, costs 
were found to be $3,596,236 total capital investment and a $1,178,927 
total annualized cost. The estimated EtO emissions reductions are 1.5 
tpy with a cost effectiveness of $783,816 per ton of EtO. There are no 
cost or emission impacts for Option 2.
    As discussed in section III.C.2, 99.94 percent emission reduction 
(Option 1) reflects the current developments in processes and 
technology by this industry (i.e., well performing air pollution 
control). While Option 2 would prevent backsliding, it does not achieve 
additional emission reduction.

[[Page 22840]]

Therefore, pursuant to CAA section 112(d)(6), we are proposing to 
revise the standard for SCVs at facilities where EtO use is at least 10 
tpy. Specifically, we are proposing to require facilities where EtO use 
is at least 10 tpy to reduce their emissions from new and existing SCVs 
by 99.94 percent. This is the same standard that was proposed pursuant 
to CAA section 112(f)(2) as discussed in section III.C. We solicit 
comment on this proposed standard (Comment C-41).
2. SCV at Facilities Where EtO Use Is at Least 1 Tpy but Less Than 10 
Tpy
    The current subpart O contains emission standards for SCVs at 
facilities where EtO use is at least 1 tpy but less than 10 tpy. There 
are 18 facilities where EtO use is at least 1 tpy but less than 10 tpy, 
all of which have SCVs. Of these facilities, 10 currently use catalytic 
oxidizers to control their SCV emissions, three use gas/solid reactors, 
three use wet scrubbers, one uses a wet scrubber and catalytic oxidizer 
in series, and one uses a wet scrubber and gas/solid reactor in series. 
Performance tests are available for SCVs at 10 facilities where EtO use 
is at least 1 tpy but less than 10 tpy; seven of these facilities use 
catalytic oxidizers, and three use wet scrubbers. We reviewed these 
performance tests, and the reported emission reductions ranged from 
99.2 percent to 99.9999 percent.
    We considered two potential options as part of the technology 
review. The first option we considered (Option 1) is maximum SCV 
emission reduction with which compliance can be demonstrated at all 
facilities where EtO use is at least 1 tpy but less than 10 tpy 
considering current emission profiles. This emission reduction is 99.8 
percent. The second option we considered (Option 2) is the maximum SCV 
emission reduction that all facilities where EtO use is at least 1 tpy 
but less than 10 tpy are currently meeting, which is 99.2 percent. 
These standards were considered as part of the analysis pursuant CAA 
section 112(f)(2) as discussed in section III.C.2. The impacts of 
Option 1 are presented in Table 22 as Control Option C. There are no 
cost or emission impacts for Option 2.
    As discussed in section III.C.2, the emission reduction 
requirements under Option 1 reflect the current developments in 
processes and technology by this industry (i.e., well performing air 
pollution control). While Option 2 would prevent backsliding, it does 
not achieve additional emission reduction. Therefore, pursuant to CAA 
section 112(d)(6), we are proposing to revise the standard for new and 
existing SCVs at facilities where EtO use is at least 1 tpy but less 
than 10 tpy. Specifically, we are proposing to require facilities where 
EtO use is at least 1 tpy but less than 10 tpy to reduce their SCV 
emissions by 99.8 percent. This is the same standard that was proposed 
pursuant to CAA section 112(f)(2) as discussed in section III.C. We 
solicit comment on these proposed standards (Comment C-42).
3. ARV at Facilities Where EtO Use Is at Least 10 Tpy
a. Existing Sources
    The current subpart O contains emission standards for ARVs at 
facilities where EtO use is at least 1 tpy but less than 10 tpy. As 
discussed in section III.B.2 of this preamble, we are proposing to 
remove the 1 ppmv alternative for ARVs at facilities where EtO use is 
at least 10 tpy. There are 47 facilities where EtO use is at least 10 
tpy, 41 of which have ARVs. Of these facilities, 22 currently use 
catalytic oxidizers, seven use gas/solid reactors, four use wet 
scrubbers, three use thermal oxidizers, three use a wet scrubber and 
gas/solid reactor in series, two use a catalytic oxidizer and gas/solid 
reactor in series, and one uses a catalytic oxidizer and thermal 
oxidizer in series. Performance tests are available for 32 ARVs at all 
facilities where EtO use is at least 10 tpy; 19 currently use catalytic 
oxidizers, four use gas/solid reactors, two use wet scrubbers, two use 
a wet scrubber and gas/solid reactor in series, four use thermal 
oxidizers, and one uses a catalytic oxidizer and gas/solid reactor in 
series. We reviewed these performance tests, and the reported emission 
reductions ranged from 95.7 percent to 99.998 percent.
    For existing ARVs at facilities where EtO use is at least 10 tpy, 
we considered two potential options as part of the technology review. 
The first option we considered (Option 1) is the emission reduction 
that has been demonstrated in 75 percent of all available performance 
tests, which is 99.6 percent. The second option we considered (Option 
2) is the emission reduction that has been demonstrated in 50 percent 
of all available performance tests, which is 99.9 percent.
    The impacts of these options are presented in Table 30:

  Table 30--Nationwide Emissions Reduction and Cost Impacts of Options Considered Under CAA Section 112(d)(6) for Existing ARVs at Facilities Where EtO
                                                                 Use Is at Least 10 TPY
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                           Total capital                   EtO emission        Cost
                     Option                                 Proposed standard               investment     Total annual     reductions     effectiveness
                                                                                                ($)        costs  ($/yr)       (tpy)        ($/ton EtO)
--------------------------------------------------------------------------------------------------------------------------------------------------------
1..............................................  99.6 percent emission reduction........      $5,348,248      $1,389,805            1.89        $734,581
2..............................................  99.9 percent emission reduction........      20,563,093       4,504,268            2.96       1,521,440
--------------------------------------------------------------------------------------------------------------------------------------------------------

    We are proposing Option 1 because Option 1 would be more cost-
effective. Therefore, pursuant to CAA section 112(d)(6), we are 
proposing to revise the standard for existing ARVs at facilities where 
EtO use is at least 10 tpy under CAA section 112(d)(6). Specifically, 
we are proposing to require these facilities to continuously reduce 
emissions from existing ARVs by 99.6 percent. We are soliciting comment 
on our proposed revision to this standard (Comment C-43). In addition, 
for the same reason discussed above in section III.B.1.a, we solicit 
comment on whether to include an alternative lb/hr limit that is 
equivalent to 99.6 percent emission reduction for existing ARVs at 
facilities where EtO use is at least 10 tpy and whether 9.8E-4 lb/hr, 
which we calculated using the method described in section III.B.1.a, is 
an appropriate alternative standard that is equivalent to the proposed 
99.6 percent emission reduction standard for existing ARVs at 
facilities where EtO use is at least 10 tpy (Comment C-44).
b. New Sources
    The current subpart O contains emission standards for new ARVs at 
facilities where EtO use is at least 10 tpy. As discussed in section 
III.B.2 of this preamble, we are proposing to remove the 1 ppmv 
alternative for ARVs at facilities where EtO use is at least 10 tpy. 
For new ARVs at facilities where EtO use is at least 10 tpy, we 
considered the same two potential options as those

[[Page 22841]]

evaluated for existing ARVs at facilities where EtO use is at least 10 
tpy for the same reasons explained above. The first potential option 
(Option 1) would require achieving 99.6 percent emission reduction, and 
the second potential option (Option 2) would require achieving 99.9 
percent emission reduction. The impacts of these options, which are 
presented in Table 31 of this preamble, are based on a model plant for 
new ARVs at a facility using at least 10 tpy EtO with the following 
assumptions reflecting the average of each of the parameters at 
existing facilities at least 10 tpy EtO:
     Number of ARVs: 6.
     Annual EtO use: 150 tpy.
     Annual operating hours: 8,400.
     Portion of EtO going to ARVs: 3.90 percent.
     ARV flow rate: 300 cfs.

Table 31--Model Plant Emissions Reduction and Cost Impacts of Options Considered Under CAA Section 112(d)(6) for New ARVs at Facilities Where EtO Use Is
                                                                     at Least 10 TPY
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                           Total capital                   EtO emission        Cost
                     Option                                 Proposed standard               investment     Total annual     reductions     effectiveness
                                                                                                ($)        costs  ($/yr)       (tpy)        ($/ton EtO)
--------------------------------------------------------------------------------------------------------------------------------------------------------
1..............................................  99.6 percent emission reduction........        $272,825         $90,990          3.5E-2      $2,592,644
2..............................................  99.9 percent emission reduction........         400,076         115,974          5.3E-2       2,203,031
--------------------------------------------------------------------------------------------------------------------------------------------------------

    We are proposing Option 2 because Option 2 would achieve greater 
emission reductions than Option 1, and Option 2 would be more cost-
effective. Therefore, pursuant to CAA section 112(d)(6), we are 
proposing to revise the standard for new ARVs at facilities where EtO 
use is at least 10 tpy under CAA section 112(d)(6). Specifically, we 
are proposing to require these facilities to continuously reduce 
emissions from new ARVs by 99.9 percent. We are soliciting comment on 
our proposed revision to this standard (Comment C-45). In addition, for 
the same reason discussed in section III.B.1.a of this preamble, we 
solicit comment on whether to include an alternative lb/hr limit that 
is equivalent to 99.9 percent emission reduction for new ARVs at 
facilities where EtO use is at least 10 tpy and whether 2.3E-4 lb/hr, 
which we calculated using the method described in section III.B.1.a, is 
an appropriate alternative standard that is equivalent to the proposed 
99.9 percent emission reduction standard for new ARVs at facilities 
where EtO use is at least 10 tpy (Comment C-46).

G. What other actions are we proposing, and what is the rationale for 
those actions?

    In addition to the proposed actions described above, we are 
proposing additional revisions to the NESHAP. We are proposing 
revisions to the SSM provisions of the NESHAP in order to ensure that 
they are consistent with the decision in Sierra Club v. EPA, 551 F. 3d 
1019 (DC Cir. 2008), in which the court vacated two provisions that 
exempted sources from the requirement to comply with otherwise 
applicable CAA section 112(d) emission standards during periods of SSM. 
We also are proposing revisions to performance test procedures and 
methods; revisions to monitoring, recordkeeping, and reporting 
requirements, including requirements for electronic reporting of 
emissions test results and reports; and making clarifications related 
to single-item sterilization processes. 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 (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 
that appears at 40 CFR 63.363(f). We are also proposing to eliminate 
the malfunction exemption in this rule that appears at 40 CFR 63.362(b) 
and instead require compliance with the standards at all times. 
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 and 
revise certain recordkeeping requirements related to the SSM exemption 
as further described below.
    The EPA has attempted to ensure that the provisions we are 
proposing to eliminate are inappropriate, unnecessary, or redundant in 
the absence of the SSM exemption. We are specifically seeking comment 
on whether we have successfully done so (Comment C-47).
    In proposing the standards in this rule, the EPA has taken into 
account startup and shutdown periods and, for the reasons explained 
below, has not proposed alternate standards for those periods. Emission 
reductions for SCV, ARV, CEV, and room air emission sources are 
typically achieved by routing vapors to an APCD such as a wet scrubber, 
catalytic oxidizer, and dry bed scrubber. It is common practice in this 
source category to start an APCD prior to startup of the emissions 
source it is controlling, so the APCD would be operating before 
emissions are routed to it. We expect APCDs would be operating during 
startup and shutdown events in a manner consistent with normal 
operating periods, and that these APCDs will be operated to maintain 
and meet the monitoring parameter operating limits set during the 
performance test. We have no reason to believe that emissions are 
different during startup and shutdown. Therefore, we are proposing that 
emissions from startup and shutdown activities be included when 
determining if all the standards are being attained. As currently 
proposed in 40 CFR 63.362(b), compliance with the emission limitations 
(including operating limits) in this subpart is required ``at all 
times.'' We solicit comment on whether facilities in the Commercial 
Sterilization Facilities source category will be able to comply with 
the standards during these times (Comment C-48).
    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)

[[Page 22842]]

(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).
a. 40 CFR 63.362(j) General Duty
    We are proposing to add general duty regulatory text at 40 CFR 
63.362(j) that reflects the general duty to minimize emissions while 
not including any reference to periods covered by an SSM exemption. In 
the absence of the SSM exemption, there is no need to differentiate 
between normal operations, startup and shutdown, and malfunction events 
in describing the general duty.
b. Compliance With Standards
    We are proposing to revise 40 CFR 63.632 to reflect the court order 
and correct the CFR to remove any exemptions from compliance during an 
SSM event. Revisions will clarify and remove any language that is 
premised on the existence of an exemption and is inappropriate in the 
absence of the exemption. Thus, we require compliance with standards at 
all times through additions to the regulatory text at 40 CFR 63.362(j).
c. 40 CFR 63.365 Performance Testing
    We are proposing to revise the General Provisions table (Table 7) 
entry for 40 CFR 63.7(e) by adding separate rows for 40 CFR 63.7(e)(1) 
through (4) and by changing the ``yes'' for 40 CFR 63.7(e)(1) to a 
``no.'' Section 63.7(e)(1) describes performance testing requirements. 
The EPA is instead proposing to modify the performance testing 
requirements at 40 CFR 63.365(d). The performance testing requirements 
that we are proposing to modify differ from the General Provisions 
performance testing provisions in several respects. The regulatory text 
does not include the language in 40 CFR 63.7(e)(1) that restated the 
SSM exemption and language that precluded startup and shutdown periods 
from being considered ``representative'' for purposes of performance 
testing. The proposed performance testing provisions will exclude 
periods of startup or shutdown as representative conditions for 
conducting performance testing. As in 40 CFR 63.7(e)(1), performance 
tests conducted under this subpart should not be conducted during 
malfunctions because conditions during malfunctions are often not 
representative of normal operating conditions. The EPA is proposing to 
add language that requires the facility to record the process 
information that is necessary to document operating conditions during 
the test and include in such record an explanation to support that such 
conditions represent normal operation. Section 63.7(e) requires that 
the facility make available to the Administrator upon request 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.
d. Monitoring
    We are proposing to revise the General Provisions table (Table 7) 
entry for 40 CFR 63.8(c)(1)(iii) by changing the ``yes'' to a ``no.'' 
The cross-references to the SSM plan requirements in that paragraph are 
not necessary in light of other requirements of 40 CFR 63.8 that 
require good air pollution control practices (40 CFR 63.8(c)(1)) and 
that set out the requirements of a quality control program for 
monitoring equipment (40 CFR 63.8(d)).
    We are proposing to revise the General Provisions table (Table 7) 
entry for 40 CFR 63.8(d) by adding separate rows for 40 CFR 63.8(d)(1) 
through (3) and changing the ``yes'' to a ``no'' for 40 CFR 63.8(d)(3). 
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 63.367 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 40 CFR 63.8(d)(2).''
e. 40 CFR 63.367 SSM-Related Recordkeeping
    The regulations in 40 CFR 63.10(b)(2)(i) describe the recordkeeping 
requirements during startup and shutdown. It will continue to be 
important to know when such startup and shutdown periods begin and end 
in order to determine compliance with the appropriate standard for 
normal operations or any separate standard for startup and shutdown. We 
are proposing to add recordkeeping requirements to 40 CFR 63.367 that 
require recordkeeping of startup, shutdown events and require reporting 
related to all exceedances.
    We are proposing to revise the General Provisions table (Table 7) 
entry for 40 CFR 63.10(b)(2)(ii) by changing the ``yes'' to a ``no.'' 
Section 63.10(b)(2)(ii) describes the recordkeeping requirements for 
malfunction. We are instead proposing to add recordkeeping requirements 
that require reporting of malfunction events and require reporting 
related to all exceedances. The EPA is proposing that this requirement 
apply to all malfunction events requiring that the source record the 
date, time, cause, and duration of the malfunction and report any 
failure to meet the standard. The EPA is also proposing to add to 40 
CFR 63.367 a requirement that sources keep records that includes the 
affected source or equipment, whether the failure occurred during a 
period of startup, shutdown or malfunction, actions taken to minimize 
emissions, an estimate of the quantity of each regulated pollutant 
emitted over the standard for which the source failed to meet the 
standard, and a description of the method used to estimate the 
emissions. Examples of such methods would include product-loss 
calculations, mass balance calculations, measurements when available, 
or engineering judgment based on known process parameters. The EPA is 
proposing to require that sources keep records of this information to 
ensure that there is adequate information to allow the EPA to determine 
the severity of any failure to meet a standard, and to provide data 
that may document how the source met the general duty to minimize 
emissions when the source has failed to meet an applicable standard.
f. 40 CFR 63.366 SSM-Related Reporting
    When applicable, 40 CFR 63.10(b)(2)(iv)(B) requires sources to 
record actions taken during SSM events when actions were inconsistent 
with their SSM plan. The requirement is no longer appropriate because 
SSM plans will no longer be required. The requirement under 40 CFR 
63.10(b)(2)(iv)(B) to record actions to minimize emissions and record 
corrective actions is now applicable by reference to 40 CFR 63.367(g).
    We are proposing to add reporting requirements to 40 CFR 63.366 
that would require sources that fail to meet an applicable standard at 
any time to report the information concerning such events in the 
compliance report that we are also co-proposing in this action. 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

[[Page 22843]]

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.
2. Monitoring, Recordkeeping, Reporting and Testing Requirements
a. Monitoring and Testing
    Currently, the rule requires that compliance be demonstrated though 
an initial performance test and continuous parametric monitoring, with 
additional work practice standards for catalytic oxidizers. We do not 
believe that this is sufficient to ensure continuous compliance with 
the emissions limitations. We are proposing to instead require 
facilities to demonstrate continuous compliance through either an 
annual compliance demonstration and operating limits or by using EtO 
CEMS. We solicit comment on this proposed change (Comment C-49).
    The rule currently requires facilities to conduct initial 
performance testing within 180 days of the compliance date for an 
emission source. We are considering reducing the amount of time allowed 
between the compliance date and when the initial performance test is 
required in order to provide more timely assurance to affected 
communities that emission limits are being met. We solicit comment on 
what might be a more appropriate timeframe for requiring the initial 
performance test (Comment C-50).
    Due to the increasingly complex nature of control systems, we are 
also proposing to significantly revise the test methods and procedures 
requirements (40 CFR 63.365). The revised structure would be laid out 
as follows:
     Paragraph (b), currently the efficiency at the SCV, would 
be dedicated to the approved test methods used to determine the mass of 
EtO entering and exiting a control system or stack,
     Paragraph (c), currently the concentration determination, 
would provide an alternative method for determining the mass of EtO 
entering a control system if demonstrating compliance with a removal 
efficiency standard for a stream that only includes sterilization 
chamber vents,
     Paragraph (d), currently the efficiency determination at 
the aeration room vent (not manifolded), would lay out the procedures 
for determining either the removal efficiency of a control system or 
the emission rate,
     Paragraph (e), currently the determination of baseline 
parameters for acid-water scrubbers, would lay out the procedures for 
establishing the operating limit(s) for parameter monitoring for 
control devices that are used to comply with an emission limit,
     Paragraph (f) would lay out the procedures for 
establishing operating limit(s) for a process parameter where a control 
system is not used to comply with an emission limit, and
     Paragraph (g) would lay out the procedures for 
demonstrating compliance with EPA Method 204 and establishing an 
operating limit for PTE.
    We are proposing to remove EPA Test Methods 2D, 18, and 25A, as 
well as California Air Resources Board (CARB) Method 431, from the list 
of approved methods within the rule. For EPA Method 2D, we are unaware 
of any facilities currently using Roots type meters to determine flow 
rate. EPA Methods 18 and 25A, as well as CARB Method 431, are currently 
required for SCV in the subpart O rule. EPA Method 25A uses a flame 
ionization detector to count carbon atoms, and EPA Method 18 typically 
uses flame ionization detector or a photoionization detector (with a 
column that separates the hydrocarbons to speciate the compounds. CARB 
Method 431 has a lower detection limit of roughly 0.2 ppmv, and EPA 
Method 18 also uses techniques that allow detection of EtO 
concentrations to 0.2 ppmv (or 200 ppbv). Based on our proposed changes 
to the emissions standard, facilities will likely have to achieve much 
lower EtO concentration levels from commercial sterilization processes 
and control systems, and a more robust measurement technology is 
needed. Some states already require EtO emissions to be reduced to 
lower levels at 99.9 percent or greater or 0.2 ppmv (Illinois 2019). If 
the outlet from the control system is, for example 30 ppbv, the current 
test methods included in subpart O, such as Method 18, may not reliably 
detect this level of concentration. There are many performance tests in 
this source category conducted with Method 18, CARB Method 431, and 
Method 25A that report outlet concentrations as non-detect (and provide 
the detection level value as the lowest possible concentration 
detected). With non-detect concentrations at the outlet, facilities may 
not be able to demonstrate compliance with the removal efficiency 
standard or the emission rate standards. We solicit comment on the 
removal of these approved test methods (Comment C-51).
    We are also proposing to add EPA Test Methods 1 \54\ and 320 \55\ 
to the list of approved methods within the rule. Method 1 would be used 
for determining the location of sampling ports. EPA Method 320 for 
Fourier Transform Infrared Spectroscopy (FTIR) uses the absorption of 
the infrared (IR) spectrum to identify compounds, where each compound 
produces a unique absorption pattern or spectrum. The sensitivity of 
this approach is often reliant on the complexity of the emission stream 
and the presence of potential spectral interferences. For EtO 
commercial sterilization, the emission streams are not very complex and 
the primary spectral interferences (i.e., water and carbon dioxide) are 
minimal. Furthermore, EPA Method 320 using an optically enhanced FTIR 
is capable of measuring in-stack EtO concentration to approximately 10 
ppbv which is consistent with the proposal emission standards. We 
solicit comment on the addition of these test methods as well as 
solicit comment on other techniques or methods with detection levels in 
the range of EPA Method 320 (Comment C-52).
---------------------------------------------------------------------------

    \54\ See Sample/Velocity Traverses, available at https://www.epa.gov/emc/method-1-samplevelocity-traverses.
    \55\ Measurement of Vapor Phase Organic and Inorganic Emissions 
by Extractive Fourier Transform Infrared Spectroscopy.
---------------------------------------------------------------------------

    Currently, the performance test that is required to be conducted to 
determine the control efficiency for the SCV is conducted on a single 
chamber that contains no product, and it is only conducted on the first 
evacuation of the sterilization chamber. In addition, facilities are 
required to perform three 1-hour test runs. In assessing the 
performance testing procedures for the source category, the EPA 
followed the Clean Air Act National Stack Testing Guidance issued in 
2009. The intent of the 2009 stack testing guidance was to improve 
uniformity on how stack tests are conducted to demonstrate compliance 
for NESHAP (40 CFR parts 61 and 63) programs (and also New Source 
Performance Standards in 40 CFR part 60).\56\ In the Stack Testing

[[Page 22844]]

Guidance document, the EPA recommends that performance tests be 
performed under representative (normal) conditions that:
---------------------------------------------------------------------------

    \56\ The 2009 Clean Air Act National Stack Testing Guidance 
document, available at https://www.epa.gov/sites/default/files/2013-09/documents/stacktesting1.pdf, addresses the timeframe for 
conducting stack tests (i.e., granting an extension), stack test 
waivers, stack notifications to the delegated agency, observation of 
stack tests by the delegated agency, representative testing 
conditions, stopping a stack test once started, postponement of a 
stack test, and information to include in the test report.

--represent the range of combined process and control measure 
conditions under which the facility expects to operate (regardless of 
the frequency of the conditions); and
--are likely to most challenge the emissions control measures of the 
facility with regard to meeting the applicable emission standards, but 
without creating an unsafe condition. (EPA 2009)

    Concerns with the current testing procedures in subpart O include 
that testing is conducted on a single sterilizer chamber while no 
product is present, and testing is conducted for the first evacuation 
only, neither of which may be representative of actual nor normal 
operations. Each sterilization cycle is conducted on product and 
packaging in the sterilizer chamber, with a set charge of EtO and a 
defined number of nitrogen and air washes. To incorporate the 2009 
stack testing guidance, the performance testing should be conducted 
during normal sterilizer chamber conditions. This change to the 
performance testing procedure would provide an emission reduction 
percentage from the performance test that more closely reflects the 
emission reduction achieved during normal operation. To address both 
the maximum capacity and the low emissions loading criteria in the 2009 
Stack Testing Guidance, the full series of nitrogen and air washes of 
the sterilization cycle could be included in the performance test 
period. For the first nitrogen wash, the maximum capacity of the EtO 
concentration would be addressed, and with each additional nitrogen 
wash and air wash of the sterilization cycle, the EtO concentration 
inlet to the control system will decline and further challenge the 
emission removal efficiency of the control system. Because multiple 
emission sources may be vented to the APCD at one time, the performance 
testing procedure should also include the normal, simultaneous routing 
of emissions sources to an APCD typically seen during operation.
    The EPA has determined that the current performance testing 
procedures in subpart O do not reflect normal operations as discussed 
in the 2009 Stack Testing Guidance. A more encompassing performance 
test procedure for SCVs that includes normal operation of the 
sterilizer chamber with product present, covers all evacuations, i.e., 
all venting and washes, and also includes the number of sterilizer 
chambers (or other emission sources) that typically vent simultaneously 
would provide a more representative control level actually achieved by 
the control system. A longer test run period would provide a better 
indication of the emission reduction achieved by the APCD over time 
with multiple normal processes routing to the device. For CEV and ARV 
emission sources, a longer test run period would provide the time-
averaged emission reduction achieved by the APCD with multiple, 
normally operating processes routing to the device.
    The EPA is proposing a 24-hour test run across all emission source 
types, SCV, CEV, ARV, and room air for facilities where EtO use is at 
least 10 tpy. We are proposing that the performance testing be 
conducted under normal operating conditions and each test run be 
conducted for 24 hours. For facilities where EtO use is less than 10 
tpy, the EPA is proposing that each test run within the test may 
instead be conducted for a 1-hour period.
    When determining the volumetric flow rate during performance 
testing, we currently require that ``the flowrate must be constant 
during time (t).'' We are unsure of whether this is feasible or 
necessary, and we request comment on whether this language should be 
modified and, if so, how (Comment C-53).
    In addition, we believe that the current language surrounding 
standard volume is unclear, and we are proposing to revise our 
description of standard volume to read as follows: ``24.05 liters per 
gram-mole (L/g-mole) at 20 [deg]C and 101.325 kilopascals (kPa) (385.1 
standard cubic feet (scf) per pound-mole (scf/lb-mole) at 68 [deg]F and 
1 atmosphere). We solicit comment on our proposed revisions to language 
regarding standard volume (Comment C-54).
    The APCD and process parameters that are selected for monitoring 
should be key indicators that confirm the control system or process is 
operating properly and that the emission limit(s) is being met. The 
operating limits that are set for these parameters are important as 
they help to ensure that conditions are similar to those that occurred 
during the most recent compliance demonstration with the emissions 
standards. Monitoring these APCD and process parameters ensures that 
ongoing operations are within the range of values that occurred during 
the compliance demonstration. Maintaining the APCD and process 
parameters within the operating limits established during the 
performance test helps ensure the emission standard is being met. Note 
that APCD and process operating parameters need to be collected during 
each periodic performance test and perhaps revised because of the 
performance test. Moreover, when substantial process changes occur or 
control devices change, performance testing along with concurrent 
parameter data collection must occur, and the operating limit for the 
parameter be adjusted or reaffirmed, as required.
    During the initial and annual performance testing, the operating 
limits for APCD and process parameters are determined. For the most 
part, the APCD parameters required in the EtO Commercial Sterilization 
NESHAP are appropriate and will continue to be monitored, however more 
explicit procedures for establishing the operating limits are needed in 
the rule. The current procedure for determining operating limits 
typically includes measuring and recording the parameter value every 15 
minutes over three test runs and calculating the average parameter 
value for each test run. The average value from the test runs will be 
the minimum or maximum operating limit, depending on the parameter, for 
the APCD.
    We are proposing several changes to how operating limits are 
established during and monitored between compliance demonstrations. The 
parameters selected for ongoing monitoring of control devices are 
generally related to the key operating principles for the type of 
control device.
    For acid-water scrubbers, the current operating limits that are 
allowed in the rule include the maximum ethylene glycol (EG) 
concentration in the scrubber liquor and the maximum height of scrubber 
liquor in the recirculation tank(s). We are not proposing any changes 
to how the maximum EG concentration is established. We are, however, 
proposing to add requirements regarding how the maximum scrubber liquor 
tank level is established. Currently, the rule states that ``For 
determining the scrubber liquor tank level, the sterilization facility 
shall establish the maximum liquor tank level based on a single 
measurement of the liquor tank level during one test run.'' We believe 
that a single measurement at an unspecified time during the performance 
test will

[[Page 22845]]

not provide a representative operating limit that would ensure 
compliance with the emission limit between performance tests. We are 
proposing to instead require facilities that chose to establish a 
maximum scrubber liquor tank level(s) as their operating limit for 
acid-water scrubbers to monitor and record the maximum scrubber liquor 
tank level once during each of the three test runs. We would further 
require them to use the data collected during the most recent 
performance test to calculate the average scrubber liquor tank level 
measured during the performance test. This scrubber liquor tank level 
would be the maximum operating limit for the scrubber liquor tank. This 
procedure would be conducted for every scrubber liquor tank that is 
included in the performance test. We are soliciting comment on these 
proposed changes to how the maximum scrubber liquor tank level is 
established (Comment C-55).
    We are also proposing to allow facilities with acid-water scrubbers 
to establish a maximum scrubber liquor pH as an alternative to a 
maximum EG concentration or scrubber liquor tank level. The pH of the 
scrubber liquor is a good indicator of performance and has been 
implemented in other rules that we have promulgated (e.g., the New 
Source Performance Standards for Commercial and Industrial Solid Waste 
Incineration Units at 40 CFR part 60, subpart CCCC). In addition, based 
on responses to our data collection efforts, at least 12 facilities are 
already monitoring this parameter in addition to what we currently 
require. This limit would be established in a similar manner to our 
proposed changes for establishing the scrubber liquor tank level in 
that facilities would be required to monitor and record the scrubber 
liquor pH at least once every 15 minutes during each of the three test 
runs. They would then use the data collected during the most recent 
performance test to calculate the average scrubber liquor pH measured 
during the performance test. This scrubber liquor pH would be the 
maximum operating limit for the acid-water scrubber, and these 
procedures would be conducted for every acid-water scrubber that is 
included in the performance test. We would also require that the 
instrumentation used for monitoring the scrubber liquor pH meet the 
following requirements.
     The pH sensor must be installed in a position that 
provides a representative measurement of scrubber liquor pH;
     The facility must ensure the sample is properly mixed and 
representative of the fluid to be measured;
     A performance evaluation of the pH monitoring system must 
be conducted in accordance with the facility's monitoring plan at least 
once each process operating day; and
     The facility must conduct a performance evaluation 
(including a two-point calibration with one of the two buffer solutions 
having a pH within 1 of the pH of the operating limit) of the pH 
monitoring system in accordance with the facility's monitoring plan at 
the time of each performance test but no less frequently than 
quarterly.
    We solicit comment on allowing facilities with acid-water scrubbers 
to establish a maximum scrubber liquor pH and our proposed requirements 
for instrumentation and establishing the operating limit (Comment C-
56).
    In 1994, we promulgated requirements for facilities to establish a 
minimum operating temperature for their catalytic or thermal oxidation 
units during the performance test if they were used to comply with an 
emission limitation. In 2001, this requirement was removed, and the 
operating limit consisted of the manufacturer's recommended minimum 
operating temperature. This change was made under the old testing 
paradigm of the rule where, for SCVs, the performance test was only 
conducted for one empty chamber during one phase of the cycle 
(evacuation). Control systems are much more complex, with multiple 
sterilizer chambers at different phases exhausting to the same control 
system simultaneously, often with other emission source types. 
Therefore, establishing a minimum operating temperature during the 
performance test is appropriate. Temperature as the operating parameter 
for thermal oxidizers will be maintained in the rule. We are proposing 
that the current use of manufacturer recommended minimum oxidation 
temperatures for catalytic and thermal oxidizers be replaced with site-
specific temperatures determined during the performance test.
    For thermal oxidizers, we are proposing that facilities would 
measure and record the temperature every 15 minutes over three test 
runs, calculate the average temperature for each test run, and the 
average of the three test runs would be calculated and would be the 
minimum operating limit. For catalytic oxidizers, the average of the 
three test runs would be calculated for both the inlet temperature to 
the catalyst bed and the temperature difference across the catalyst 
bed, where these values would be the minimum operating limits. For 
temperature measurement, we are proposing that the facility install, 
calibrate, operate, and maintain a temperature monitor with a minimum 
accuracy of 1 percent over the normal range of the 
temperature measured, expressed in degrees Celsius, or 2.8 degrees 
Celsius, whichever is greater. We are also proposing that the accuracy 
of the temperature monitor be verified twice each calendar year with a 
reference temperature monitor (traceable to National Institute of 
Standards and Technology (NIST) standards or an independent temperature 
measurement device dedicated for this purpose). During accuracy 
checking, the probe of the reference device shall be at the same 
location as that of the temperature monitor being tested. As an 
alternative, the accuracy of the temperature monitor may be verified in 
a calibrated oven (traceable to NIST standards). We are soliciting 
comment on the changes to establishing the operating limits for 
temperature and verifying the instrument two times per year (Comment C-
57).
    Gas-solid reactors (i.e., dry bed scrubbers) are now commonly used 
at commercial sterilization facilities. We are aware of certain 
operating parameters for this type of control device, including 
pressure drop and temperature across the dry bed packing. However, we 
believe that these are not viable parameters to monitor as indicators 
of EtO removal because neither indicate that the reaction is occurring 
on the media bed nor the remaining activity of the dry bed media, and 
that the only way to ensure continuous compliance is using an EtO CEMS. 
Therefore, we are proposing that, for control systems where a gas-solid 
reactor is present, facilities must demonstrate continuous compliance 
with the appropriate emission rate standard using an EtO CEMS. We 
solicit comment on (1) The viability of pressure drop and temperature 
across the solid packing for parametric monitoring as indicators of EtO 
removal or EtO concentration level, along with data demonstrating the 
viability for continuous compliance purposes, (2) other parameters for 
which an operating limit could be established, along with data 
demonstrating the viability of such parameters for continuous 
compliance purposes, and (3) requiring the use of an EtO CEMS for 
control systems where a gas-solid reactor is present (Comment C-58).
    It is possible to demonstrate compliance with an emission rate 
standard without the use of a control system. However, operating limits 
must still be established and monitored to confirm that operation of 
the process stays within the range(s) established

[[Page 22846]]

during the most recent compliance demonstration. Typical process 
parameters for EtO commercial sterilization could include the mass of 
EtO charged to the sterilizer chamber cycle and the EtO concentration 
of the room or vent. We are proposing that if any portion of the SCV(s) 
at a facility is neither routed to a control system nor monitored using 
an EtO CEMS, the facility must establish as an operating limit and 
monitor the maximum daily amount of EtO charged to the sterilization 
chamber(s). We are also proposing that if the ARV(s), Group 1 room air 
emissions, or Group 2 room air emissions at a facility are subject to 
an emissions limitation and if the emissions are neither routed to a 
control system nor monitored using an EtO CEMS, the facility must 
establish as an operating limit the maximum EtO concentration for each 
aeration room and area where there are Group 1 or Group 2 room air 
emissions, as applicable. We are further proposing that the facility 
monitor and record every 15 minutes the EtO concentration within each 
of these areas and compute three-hour rolling averages that must be 
maintained below the appropriate operating limits. We are also 
proposing that an affected facility must develop a site-specific 
monitoring plan for the operation of the measurement systems used to 
monitor room air EtO concentration, and we are also proposing a set of 
requirements for these monitoring plans in 40 CFR 63.364(c)(5) of the 
proposed rule. We are soliciting comment on these proposed changes for 
process parameter monitoring when no control system or EtO CEMS is 
present (Comment C-59).
    For facilities where a PTE is required (as discussed in sections 
III.B.8 and III.D.1 of this preamble), we are proposing to give 
facilities the option to either establish a minimum volumetric flow 
rate through the exhaust duct(s) or stack(s) or install, operate, 
calibrate, and maintain a continuous pressure differential monitoring 
system to verify the presence of PTE. If a facility chooses to use a 
continuous differential pressure monitoring system, a monitor must be 
installed within each room that is included in the PTE, and the 
pressure differential must be maintained above 0.007 inches of water. 
Regardless of whether a facility chooses to establish a minimum 
volumetric flow rate(s) or monitor pressure differential, we are also 
proposing that facilities continuously verify the direction of air flow 
through daily inspections of each natural draft opening (NDO), which 
may be done through a smoke test or using streamers. We are soliciting 
comment on the continuous compliance requirements for facilities 
implementing a PTE (Comment C-60).
b. EtO CEMS
    The use of CEMS is an option in the current rule for the 
measurement of EtO from the exhaust of catalytic or thermal oxidation 
controls for the purpose of parametric monitoring of those control 
options. The current rule includes two options for CEMS, one reliant on 
gas chromatography (GC) systems for the direct measurements of EtO 
(Performance Specification 9 of 40 CFR part 60, appendix B) and another 
which uses an appropriate detector to determine a surrogate, volatile 
organic compound value as EtO (Performance Specification 8 of 40 CFR 
part 60, appendix B). The current rule requires these systems to be 
capable of measuring and recording once per hour and that the facility 
record a 24-hour average of the EtO measurements. These recordkeeping 
requirements are unique to subpart O but are inconsistent with the 
requirements in the general provisions 40 CFR 63.8(c)(4)(ii) which 
require systems to be capable of measuring once each 15-minutes. While 
the current requirements in the rule may be appropriate for parametric 
monitoring, the use of speciated EtO CEMS for compliance purposes is 
warranted and therefore we are proposing (1) to remove Performance 
Specification 8 as an option for continuous monitoring because it is 
not selective to EtO and (2) that systems be capable of completing a 
collection, transport, and analysis cycle at least once each 15-minutes 
to be consistent with the General Provisions. Note that source 
facilities may choose to time-share their CEMS among different 
measuring points, provided that the measurement points are 
approximately equidistant from the CEMS, the sampling time at each 
measurement point is at least 3 times as long as the response time for 
that point, and that each measurement point has at least one complete 
cycle within 15 minutes. Of course, we propose that a complete 
description of the time-shared CEMS must be provided in the facility's 
monitoring plan. As an example, consider an EtO CEMS with a response 
time of 60 seconds and a cycling time of 75 seconds. Could it be used 
for time-sharing purposes, and if so, how many points could be sampled? 
Three times the response time would be 180 seconds, which when added to 
twice the response time (from the CEMS to the measurement point and 
back), or 120 seconds, would be 300 seconds, so the EtO CEMS could be 
used. Fifteen minutes divided by 300 seconds would yield three 
measurement points, so a facility could sample from up to three points 
for this case. Note that daily calibration checks would need to be 
provided for each measurement point and that a facility may choose to 
provide fewer than the maximum number of measurement points on an EtO 
CEMS in order to have more data from which to calculate an hourly 
average. Also, a fewer number of measurement points per EtO CEMS could 
mean fewer numbers of excess emissions, for should the CEMS malfunction 
or become out-of-control, each shared measurement point would also be 
subject to a malfunction or would be out-of-control until corrections 
were made. We are soliciting comment on the removal of PS 8, the 
requirement to monitor every 15 minutes, and allowing time-share use of 
an EtO CEMS (Comment C-61). The techniques for measuring EtO in 
stationary sources have significantly improved since the risk and 
technology review (71 FR 17712, April 7, 2006), and to account for 
these changes the EPA is proposing a new set of standards for the 
operation of these measurement techniques as CEMS. EPA is aware of at 
least two optical based technologies (e.g., FTIR and Cavity Ringdown 
Spectroscopy) being applied to continuous measurements of EtO in 
commercial sterilizer sector. In order to provide a pathway for these 
technology in the rule, EPA is also proposing a new Performance 
Specification (PS) 19 in 40 CFR part 60, appendix B, to allow for the 
use of these and other EtO CEMS sampling and analytical technologies as 
long as the required performance criteria set out in the performance 
specification are met. Initial minimum requirements for instruments are 
contained in the PS, while ongoing quality assurance (QA) and quality 
control procedures are found in QA Procedures. To that end, we are also 
proposing QA Procedure 7 in 40 CFR part 60, appendix F, to establish 
consistent requirements for ensuring and assessing the quality of data 
measured by a EtO CEMS on an ongoing basis. These requirements will 
ensure that the EtO CEMS have the ability to make appropriate 
measurements and continue to make these measurements appropriately, as 
well as to demonstrate compliance with the emission limits. These 
proposed procedures are based on techniques found in the recently 
promulgated Performance Specification 18 (PS-18) in CFR part 60, 
appendix B, and QA Procedure 6 in CFR part 60,

[[Page 22847]]

appendix F, relying on a performance-based approach used for HCl CEMS 
in PS-18 and on adherence to the continual QA Procedure for their 
operation. However, the PS and QA Procedures proposed in this rule 
contain criteria specifically devised for operation at EtO commercial 
sterilizers. We believe performance-based techniques, along with their 
associated QA procedures, offer a viable path for introducing and using 
new measurement approaches quickly. We solicit comment on the use of 
performance-based approaches and on the proposed PS and QA Procedures 
(Comment C-62). In addition, we are proposing that CEMS data be 
reported daily so that results can be shared with the public on a daily 
basis. We are soliciting comment on the frequency of CEMS data 
reporting, as well as the period that the reported CEMS data are to be 
shared with the public (Comment C-63).
    This proposed PS-19 and associated QA procedures represent a 
significant adjustment in how the Agency uses CEMS for organic HAPS, 
specifically the application of CEMS for sub ppmv-level measurements. 
With these levels of measurements, there is a need to be more 
prescriptive as to the data quality objectives in the PS, specifically 
as to how the systems are initially certified and continually quality 
assured. For those reasons we are proposing to remove PS-9 as an option 
for continuous monitoring from the rule because (1) The data quality 
objectives of this PS are not equivalent with what is found in proposed 
PS-19 and (2) the underlying technology in PS-9 (GC) would fit within 
the performance-based structure in proposed PS-19. We solicit comment 
on the removal of PS-9 as an option from the rule for continuous 
monitoring and on whether there were any concerns that a GC based 
system could meet the requirements of proposed PS-19 (Comment C-64). 
Also, we are aware there are currently EtO CEMS in place that use FTIR 
technology at commercial sterilizers that have been successfully 
certified according to Performance Specification 15 (PS-15) of 40 CFR 
part 60, appendix B as part of existing state rules, and therefore we 
have considered its use in the proposed rule. However, we consider the 
proposed PS-19 is more appropriate for low-level standards and the 
underlying technology fits within the performance-based structure in 
proposed PS-19. We are soliciting comment on whether PS-15 should be an 
option from the rule for continuous monitoring, and if so, how could 
the lower-level measurements be addressed (Comment C-65).
    In addition, if a facility chooses to demonstrate continuous 
compliance with an emission rate standard using an EtO CEMS, we are 
proposing that the facility may comply with the applicable emission 
rate standard on a 30-day rolling average basis, where each valid 
hourly average is determined from the EtO CEMS; the sum of those valid 
hourly averages is determined for each day; and the 30-day rolling 
average is determined from the sum of that day's average plus the 
previous 29 daily averages divided by 30. We are soliciting comment on 
allowing facilities to comply with a 30-day rolling average emission 
rate if an EtO CEMS is used to demonstrate continuous compliance, as 
well as the 30-day rolling average calculation procedure (Comment C-
66).
    In the absence of NIST traceable reference gases for EtO and in an 
effort to improve the accuracy and reliability of continuous 
measurements, both for performance testing and CEMS application, in PS-
19 we are also proposing to include an appendix B for the preparation 
of certification of EtO Cylinder Gas Standards consistent with the 
procedures used in Broadly Applicable Approved Alternative Methods 
(Alt) 114 \57\ for HCl standards and Alt 118 \58\ for mercury 
standards. We are soliciting comment on PS-19 appendix B for 
preparation of gas standards (Comment C-52). Finally, we are soliciting 
comment on whether certain facilities or groups of facilities should be 
required to use CEMS to comply (Comment C-67).
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    \57\ See https://www.epa.gov/sites/default/files/2020-08/documents/alt114.pdf.
    \58\ See https://www.epa.gov/sites/default/files/2020-08/documents/alt118.pdf.
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c. Fenceline Monitoring
    The EPA has previously employed fenceline monitoring (for benzene 
as a surrogate for HAP emissions from fugitive sources) as part of a 
work practice standard for petroleum refineries, promulgated as part of 
the technology review for the source category (40 CFR part 63, subpart 
CC), to monitor and manage fugitive emissions as well as aiding in the 
monitoring of the sector's ground-level emission points (e.g., storage 
tanks, wastewater collection systems, equipment leaks, etc.). This type 
of monitoring is performed at multiple points located at the edge of a 
facility's property line, commonly known as the ``fenceline,'' and the 
results of this monitoring are used to calculate a long-term average 
(e.g., annual rolling average) of a pollutant concentration at the 
boundary. If this long-term average exceeds an ``action-level,'' then a 
facility is required to conduct the associated work practices (i.e., 
root cause and corrective action) to identify and mitigate the source 
of the excess emissions. The ``action-level'' was set at a level 
reflecting full compliance with the emissions standards for the 
emission points described above and at a concentration in which there 
was a robust measurement method (i.e., EPA Method 325B) for measuring 
benzene at and well below the action-level. This level was based on the 
highest modeled impact from the refinery sector at the fenceline using 
the emission inventories and dispersion modeling.
    EPA gave close consideration to the feasibility and utility of 
adopting a similar fenceline monitoring requirement as part of this 
proposed rule, in response to a substantial number of comments from 
front-line communities supporting the use of fenceline measurements to 
address potential room air emissions from Commercial Sterilization 
Facilities. EPA notes that room air release points from this source 
category differ from fugitive emission at refineries in important 
respects. First, the boundaries for a commercial sterilization facility 
are often the building itself or very small easements, making boundary 
line measurements problematic because these locations are unlikely to 
be representative of emissions from the release points. Typically for 
this type of monitoring, we require the fenceline monitor to be at 
least 50 meters from the source of emissions to the property boundary 
\59\ to allow for some dispersion. Second, in contrast to the large 
number of dispersed and difficult-to-monitor emission points at a 
refinery, current room air releases at commercial sterilization 
facilities are typically at ground-level and consist of uncontrolled 
building emissions through doorways, loading points, and ventilation 
exhausts, all of which can be captured while inside the building and 
routed through a vent to a control device. Moreover, the proposed PTE 
design criteria, proposed room air emission standards, and associated 
parametric monitoring discussed in section III.B.8 will effectively and 
continuously ensure these previously uncontrolled emissions are 
captured and routed to exhaust points that are subject to removal or 
emission rate standards. As a result, EPA does not believe that a 
fenceline monitor would

[[Page 22848]]

measure a significant quantity of residual EtO emissions, or identify a 
compliance issue that has not already been detected through the 
continuous monitoring requirements included in this proposal.
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    \59\ EPA Method 325A, section 8.2.1.1.
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    Given the feasibility to capture room air emissions from this 
sector through the requirements to install PTEs and continuous 
parametric monitoring of these capture systems, as well as control 
systems being proposed, we consider fenceline monitoring and the 
associated work practice requirements to be unnecessary. In addition, 
as described above, we believe fenceline monitoring could be 
technically challenging to implement for this source category given the 
physical configurations of these facilities. We solicit comment on (1) 
Whether fenceline monitoring should be required regardless of the 
proposed PTE design criteria, proposed room air emission standards, and 
continuous parametric monitoring; (2) the technical feasibility of 
fenceline monitoring and available technology able to measure at any 
potential action level; and (3) the potential cost of continuous 
fenceline monitoring and associated work practices if implemented 
(Comment C-68).
    The EPA is also considering the application of beyond the fenceline 
measurements (i.e., ambient monitoring) as part of a work practice 
standard where the proposed standards in this action are in such 
format, or as an additional measure to assure additional compliance 
assurance where the proposed standards are numeric. The EPA is 
interested in and is therefore soliciting comment on how ambient 
monitoring could be used to screen for elevated concentrations of 
ethylene oxide above the ambient baseline and how this information 
could be used to trigger a root cause analysis to identify potential 
source(s) of emission and to perform corrective action, if a potential 
source of the emissions was part of an affected source under this 
commercial sterilization proposed rule. We also solicit comment on (1) 
The feasibility of other types of air monitoring that could be applied 
to this sector for compliance assurance and the costs associated with 
this type of monitoring, (2) how frequently this monitoring should 
occur, (3) the recordkeeping and reporting requirements for this type 
of monitoring, and (4) how should any action-level be defined (Comment 
C-69).
d. Initial Summary Report
    We are proposing that facilities record and report the following 
information in the initial summary report to aid us in determining 
compliance with the proposed requirements:
     EtO use and operating hours of the facility over the 
previous 12 months
    If a sterilization facility is demonstrating continuous compliance 
through periodic performance testing, the EPA is proposing that the 
following information be included in the initial summary report:
     Control system identification (ID); \60\
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    \60\ IDs that are referenced in all reports would be generated 
by the owner or operator of the facility.
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     Control device ID;
     Control device type; and
     Recirculation tank ID if an acid-water scrubber is used to 
meet the emission limitation and if an election is made to comply with 
the maximum scrubber liquor height limit.
    The EPA is proposing that the following information be included in 
the initial summary report for each sterilization chamber at the 
facility:
     The sterilization chamber ID;
     The ID of the control system that the SCV was routed to, 
if applicable;
     The portion of SCV exhaust that was routed to the control 
system, if applicable;
     The ID of the control system that the CEV was routed to, 
if applicable; and
     The portion of CEV exhaust that was routed to the control 
system, if applicable.
    If emissions from any room in the facility are subject to an 
emission limitation (e.g., aeration room or rooms where Group 1 or 
Group 2 room air emissions are present), the EPA is proposing that the 
following information be included in the initial summary report for 
each room where there are EtO emissions:
     Room ID;
     The ID of the control system that the room air was routed 
to, if applicable;
     The portion of room air that was routed to the control 
system, if applicable; and
     Documentation of emissions occurring within the room, 
including aeration, EtO storage, EtO dispensing, vacuum pump operation, 
pre-aeration handling of sterilized material, and post-aeration 
handling of sterilized material.
    If any portion of the facility is required to be operated with PTE, 
the EPA is proposing that for each NDO inspection, facilities must 
report the same information that we are proposing to require as part of 
semi-annual summary reports, as discussed later in this section. If a 
facility is complying with the requirement to follow either the Cycle 
Calculation Approach or the Bioburden/Biological Indicator Approach to 
achieve sterility assurance in accordance with ISO 11135:2014 and ISO 
11138-1:2017, we are proposing that the facility must provide the 
approach that was used for each unique cycle.
    We are soliciting comment on the content required for the initial 
summary report (Comment C-70).
e. Semi-Annual Summary Reports
    For subsequent semi-annual summary reports, we are proposing that 
facilities record and report the following information:
     EtO use and operating hours of the facility over the 
previous 12 months;
     If the facility is demonstrating continuous compliance 
through periodic performance testing, any changes to the corresponding 
information provided in the previous summary report
     Any changes related to the sterilization chambers;
     If emissions from any room in the facility are subject to 
an emission limitation, any changes related to the individual rooms;
     If any portion of the facility is required to be operated 
with PTE, the EPA is proposing that for each NDO inspection, facilities 
must report the inspection ID, the room ID, the NDO ID, the date and 
time that the inspection started, the duration of the inspection, the 
method of inspection (smoke test or streamers), and the direction of 
air flow through the NDO (into the facility or out of the facility); 
and
     If a facility is complying with the requirement to follow 
either the Cycle Calculation Approach or the Bioburden/Biological 
Indicator Approach to achieve sterility assurance to achieve sterility 
assurance in accordance with ISO 11135:2014 and ISO 11138-1:2017, we 
are proposing that the facility must provide the approach that was used 
for each unique cycle.
    We are soliciting comment on the content required for the 
subsequent semi-annual summary reports (Comment C-71).
f. Quarterly Summary Reports
    We are proposing different reporting requirements for facilities 
where EtO use is less than 20 tpy. Specifically, we are proposing that 
these facilities submit summary reports on a quarterly basis and 
include in these reports the following additional information for each 
room whether there is the potential for EtO emissions:
     Number of RACs per hour;
     Average hourly temperature; and

[[Page 22849]]

     Average hourly EtO concentration.
    We are also proposing that these facilities may instead submit 
summary reports once every three years if they meet the following 
requirements:
     Operate all areas of the facility that contain Group 2 
room air emissions with PTE, with all exhaust gas streams being 
captured and routed to a control system or through a stack(s),
     Limit Group 2 room air emissions of EtO to 2.8E-3 lb/hr 
(facilities where EtO use is less than 20 tpy), and
     Meet the requirements of 40 CFR 63.363.
    These emission rates are the most stringent limits for which all 
facilities within these groups can demonstrate compliance using 
currently available technology. We solicit comment on different 
requirements for these facilities (Comment C-72).
g. Electronic Reporting
    The EPA is proposing that owners and operators of commercial 
sterilization facilities submit electronic copies of required 
compliance reports, performance test reports, and performance 
evaluation reports through the EPA's Central Data Exchange (CDX) using 
the Compliance and Emissions Data Reporting Interface (CEDRI). A 
description of the electronic data submission process is provided in 
the memorandum Electronic Reporting Requirements for New Source 
Performance Standards (NSPS) and National Emission Standards for 
Hazardous Air Pollutants (NESHAP) Rules, available in the docket for 
this action. Following a processing period in CEDRI, each report will 
be sent to the EPA's Web Factor and Information Retrieval (WebFIRE) 
database, where it is publicly accessible. The standard processing 
period is 60 days for performance test reports and performance 
evaluation reports and 30 days for all other report submissions. Agency 
reviewers may extend the processing period for individual reports by up 
to 60 days for performance test reports and performance evaluation 
reports and up to 30 days for all other report submissions. 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 \61\ at the time of the test are 
submitted in the format generated through the use of the ERT or an 
electronic file consistent with the extensible markup language (XML) 
schema on the ERT website, and other performance test results be 
submitted in portable document format (PDF) using the attachment module 
of the ERT. Similarly, performance evaluation results of continuous 
emissions monitoring systems (CEMS) measuring relative accuracy test 
audit (RATA) pollutants that are supported by the ERT at the time of 
the test must be submitted in the format generated through the use of 
the ERT or an electronic file consistent with the XML schema on the ERT 
website, and other performance evaluation results be submitted in PDF 
using the attachment module of the ERT. The proposed rule requires that 
Notification of Compliance Status (NOCS) reports be submitted as a PDF 
upload in CEDRI. For compliance reports, both initial and ongoing, the 
proposed rule requires that facilities use the appropriate spreadsheet 
template to submit information to CEDRI. A draft version of the 
proposed template for these reports is included in the docket for this 
rulemaking.\62\ The EPA specifically requests comment on the content, 
layout, and overall design of the template.
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    \61\ See https://www.epa.gov/electronic-reporting-air-emissions/electronic-reporting-tool-ert.
    \62\ See EtO Compliance Report Draft Template.xlsx, available at 
Docket ID. No. EPA-HQ-OAR-2019-0178.
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    While the ERT does not directly support submittal for EPA Reference 
Method 320 or ASTM D6384-12e1, a facility may complete the WebFIRE 
template with the performance test data and submit to the ERT as an 
attachment, along with a PDF version of the full performance test 
report. The WebFIRE template is included in the docket for this action. 
The EPA specifically requests comment on the content, layout, and 
overall design of the template(s) for use with EPA Method 320 and ASTM 
D6348-12e1 (Comment C-73).
    Additionally, the EPA has identified two broad circumstances in 
which electronic reporting extensions may be provided. These 
circumstances are (1) Outages of the EPA's CDX or CEDRI that preclude 
an owner or operator from accessing the system and submitting required 
reports and (2) force majeure events, which are defined as events that 
will be or have been caused by circumstances beyond the control of the 
affected facility, its contractors, or any entity controlled by the 
affected facility that prevent an owner or operator from complying with 
the requirement to submit a report electronically. Examples of force 
majeure events are acts of nature, acts of war or terrorism, or 
equipment failure or safety hazards beyond the control of the facility. 
The EPA is providing these potential extensions to protect owners and 
operators from noncompliance in cases where they cannot successfully 
submit a report by the reporting deadline for reasons outside of their 
control. In both circumstances, the decision to accept the claim of 
needing additional time to report is within the discretion of the 
Administrator, and reporting should occur as soon as possible.
    The electronic submittal of the reports addressed in this proposed 
rulemaking will increase the usefulness of the data contained in those 
reports, is in keeping with current trends in data availability and 
transparency, will further assist in the protection of public health 
and the environment, will improve compliance by facilitating the 
ability of regulated facilities to demonstrate compliance with 
requirements and by facilitating the ability of delegated state, local, 
tribal, and territorial air agencies and the EPA to assess and 
determine compliance, and will ultimately reduce burden on regulated 
facilities, delegated air agencies, and the EPA. Electronic reporting 
also eliminates paper-based, manual processes, thereby saving time and 
resources, simplifying data entry, eliminating redundancies, minimizing 
data reporting errors, and providing data quickly and accurately to the 
affected facilities, air agencies, the EPA, and the public. Moreover, 
electronic reporting is consistent with the EPA's plan \63\ to 
implement Executive Order 13563 and is in keeping with the EPA's 
Agency-wide policy \64\ developed in response to the White House's 
Digital Government Strategy.\65\ For more information on the benefits 
of electronic reporting, see the memorandum Electronic Reporting 
Requirements for New Source Performance Standards (NSPS) and National 
Emission Standards for Hazardous Air Pollutants (NESHAP) Rules, 
referenced earlier in this section.
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    \63\ The EPA's Final Plan for Periodic Retrospective Reviews, 
August 2011. Available at: https://www.regulations.gov/document?D=EPA-HQ-OA-2011-0156-0154.
    \64\ E-Reporting Policy Statement for EPA Regulations, September 
2013. Available at: https://www.epa.gov/sites/production/files/2016-03/documents/epa-ereporting-policy-statement-2013-09-30.pdf.
    \65\ Digital Government: Building a 21st Century Platform to 
Better Serve the American People, May 2012. Available at: https://obamawhitehouse.archives.gov/sites/default/files/omb/egov/digital-government/digital-government.html.
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3. Other Changes
a. Single-Item Sterilizers
    The EPA has identified nine commercial sterilization facilities 
that use single-item sterilizer processes, where all of these 
facilities have APCDs

[[Page 22850]]

in place to reduce EtO emissions. While a traditional sterilization 
chamber tends to be a larger vessel that accommodates pallets 
containing diverse products, a single-item sterilizer is generally 
smaller and may use much less EtO to sterilize products. In the single-
item sterilization process, operators place the product into a plastic 
pouch, a slight vacuum is applied, and EtO gas is injected into the 
pouch and sealed. Sealed pouches with product and EtO are placed in 
bins and then loaded into a cabinet or chamber under specific 
temperature and humidity conditions where EtO both sterilizes the 
product and off-gasses or aerates from the pouch. The EtO slowly 
dissipates from the pouch or bag by diffusion. Once the pouch and 
product are removed from the cabinet or chamber, the product is held in 
the shipping/warehouse area before being sent offsite. EtO is stored in 
a pressurized cylinder at single-item sterilization facilities, and 
these cylinders are smaller than EtO storage drums used at traditional 
sterilization facilities. Some single-item sterilizers may use EtO 
ampules, and place the ampule in the pouch, seal the pouch, then break 
the ampule prior to placement in the cabinet or chamber.
    In this proposal, the EPA is clarifying that the cabinet or 
chambers where sterilization and aeration occur at single-item 
sterilizer facilities are subject to the SCV emission standards under 
subpart O. The process activities, including the dwell period to expose 
the product to EtO and ensure sterile product, as well as aeration of 
the product to remove residual EtO, occur at single-item sterilization 
facilities in the same way as at other EtO commercial sterilization 
facilities. The cabinet or chamber includes air flow that is routed to 
a vent to an APCD or to the atmosphere. There is no technical or 
process difference between single-item sterilization and those at other 
traditional sterilizer chamber and aeration room operations that impact 
adopting measures to reduce EtO emissions. The cabinet or chamber where 
pouches are placed should be referred to as combination sterilizer 
chambers, i.e., where both sterilization and aeration occur in the same 
chamber. EtO usage at single-item sterilizer facilities range from 0.43 
to 2.5 tpy. There are five single-item sterilizer facilities where EtO 
use is at least 1 tpy but less than 10 tpy, and these facilities are 
subject to the SCV emission standard for sources using 1 to 10 tons of 
EtO per year. There are four facilities that are using less than 1 ton, 
and these facilities are subject to the SCV emission standard for 
sources using less than 1 ton. These sources were included in the ample 
margin of safety analysis for SCV at sources using 1 to 10 tons (see 
section III.D.3) and for the proposed SCV standards at facilities using 
less than 1 ton (see section III.B.1). In addition, the facilities 
would be subject to the proposed emission standards for Group 1 room 
air emissions, specifically for EtO injection room air emissions, and 
for Group 2 room air emissions (for shipping/warehouse rooms).
b. Title V
    Section 502(a) of the Clean Air Act establishes the list of sources 
required to obtain operating permits under title V. This list of 
sources includes ``any other source (including an area source) subject 
to standards or regulations under section 111 or 112 [NESHAP].'' See 40 
CFR 70.3(a) and 71.3(a). Section 502(a) provides that, ``The 
Administrator may, in the Administrator's discretion and consistent 
with the applicable provisions of this Act, promulgate regulations to 
exempt one or more source categories (in whole or in part) from the 
requirements of this subsection if the Administrator finds that 
compliance with such requirements is impracticable, infeasible, or 
unnecessarily burdensome on such categories, except that the 
Administrator may not exempt any major source from such requirements.'' 
Pursuant to this authority, the EPA published a final rule on December 
19, 2005 (70 FR 57320), that exempted area source EtO commercial 
sterilizers from title V permitting.
    In the December 2005 final rule, the EPA articulated a four-factor 
balancing test to evaluate whether title V permitting requirements 
would be ``unnecessarily burdensome'' for an area source category. The 
four factors evaluated by the EPA were: (1) Whether title V would 
result in significant improvements to the compliance requirements, 
including monitoring, recordkeeping, and reporting that are proposed 
for the area source category; (2) whether title V permitting would 
impose significant burdens on the area source category and whether the 
burdens would be aggravated by any difficulty in obtaining assistance 
from permitting authorities; (3) whether the costs of title V 
permitting for area sources would be justified taking into 
consideration any potential gains in compliance likely to occur for 
such sources; and (4) whether adequate oversight by state and local 
permitting authorities could achieve high compliance with the NESHAP 
requirements without relying on title V permitting. In addition, the 
EPA stated that ``. . . the legislative history of Section 502(a) 
suggests that EPA should not grant exemptions where doing so would 
adversely affect public health, welfare, or the environment. See 
Chafee-Baucus Statement of Senate Managers, Environment and Natural 
Resources Policy Division 1990 CAA Leg. Hist. 905, Compiled November 
1993 (in that `[t]he Act requires EPA to protect the public health, 
welfare and the environment, . . . this provision of the permits title 
prevents EPA from exempting sources or source categories from the 
requirements of the permit program if such exemptions would adversely 
affect public health, welfare, or the environment').''
    At the time of the December 2005 final rule, the EPA's analyses of 
the four-factor balancing test and consideration of the legislative 
history of section 502(a) weighed in favor of exempting area source EtO 
commercial sterilizers from title V permitting. Since that time, the 
EPA has gained a better understanding of the risks associated with EtO 
emissions. In 2016, the EPA released its updated IRIS value for EtO, 
which indicated that cancer risks from EtO emissions were significantly 
higher than characterized in the prior 1985 assessment. Subsequently, 
the 2014 National Air Toxics Assessment released in August 2018 
identified EtO emissions as an important risk driver in several areas 
across the country. Following this, the EPA has engaged in assessments 
of community census tracts that potentially have elevated cancer risks 
from exposure to EtO in ambient air. Related to these risk findings, 
there has been significant public interest in the Commercial 
Sterilization Facilities source category, including robust 
participation in public hearings and public comment on permitting 
actions.
    In addition to an improved understanding of the risks and ambient 
concentrations of EtO, the EPA has more information available to 
support this proposal's evaluation than was available during the 2005 
rulemaking. The EPA conducted its December 2019 questionnaire and 
September 2021 ICR (OMB Control No. 2060-0733) as part of this 
rulemaking, which included gathering data from area source EtO 
sterilizers related to EtO usage and emissions, parent company 
ownership, and revenue generation related to sterilization services. In 
contrast, the 2005 rulemaking was in part based upon

[[Page 22851]]

the absence of information available to the EPA at the time.\66\
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    \66\ See 70 FR 75325, December 19, 2005: ``For E.O. sterilizers, 
as in the proposal, the EPA has no reliable information on the 
economic resources of area sources but, as described below, believes 
that a number of area sources are small businesses with limited 
economic resources.''
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    In a 2019 ICR renewal for the part 70 state operating permits 
program (OMB Control No. 2060-0243), the EPA estimated the burden for 
title V permitting. At the time, the EPA estimated the average burden 
for all affected sources at $19,031 per year (in year 2018 dollars). 
This burden value was calculated based upon estimates of the labor 
hours required for title V permitting related activities, including 
application preparation, monitoring development and operation, and 
reporting. See 2nd Notice Supporting Statement for ICR No. 1587.14 OMB 
No. 2060-0243, February 2019, available in the ``40 CFR part 70 State 
Operating Permit Regulations, EPA Renewal ICR'' docket (Docket ID No. 
EPA-HQ-OAR-2004-0015). The EPA utilized the activity labor hour 
estimates from the 2019 ICR to develop a tailored estimate for this 
rulemaking of the labor hour and cost burden for area source EtO 
commercial sterilizers to comply with title V permitting requirements. 
The EPA estimates this burden at 391 labor hours and $67,211 in total 
cost (inclusive of labor and operating permit fees) for the first year 
of compliance, and 43 labor hours and $6,287 in total cost for the 
second and third years of compliance. Note that the activity labor hour 
estimates used in this burden estimate are based upon the average for 
all sources subject to the title V program, including both area sources 
and complex major sources. Compared to area sources, major sources 
experience greater burden from title V associated activities, 
particularly in application preparation, and are associated with 
increased delegated authority burden which, by law, is required to be 
passed onto sources in the form of permit fees. As a result, the 
average burden estimate is likely to overstate the costs imposed upon 
area source EtO commercial sterilizers. While this burden is not 
insignificant, it represents a small portion of the anticipated costs 
related to the amendments of this proposed rule. Further, we have 
determined that this burden is not significant and is justified when 
considering the anticipated benefits from requiring title V permitting 
for area source EtO commercial sterilizers.
    In the March 2005 proposed rule to exempt area source EtO 
commercial sterilizers from title V permitting, the EPA evaluated the 
relationship to the legislative history of section 502(a) as follows: 
``The EPA believes the vast majority of area sources proposed today for 
exemption from title V permitting in this notice are typically subject 
to not more than one NESHAP, and few other requirements under the Act, 
and that these NESHAP are relatively simple in how they apply to these 
sources. One of the primary purposes of the title V program is to 
clarify, in a single document, the various and sometimes complex 
regulations that apply to sources in order to improve understanding of 
these requirements and to help sources to achieve compliance with the 
requirements.'' (See 70 FR 15254) In contrast to the subpart O rule 
requirements as they existed at that time, the rule amendments proposed 
in this rule provide for a greater degree of complexity and 
requirements to achieve and demonstrate compliance for area sources. 
While the EPA maintains the understanding that the majority of area 
source EtO sterilizers are subject only to a single NESHAP, the 
compliance benefits of title V are greater today than in 2005.
    For the reasons articulated above, the EPA has determined that it 
is not appropriate to exempt area source EtO commercial sterilizers 
from the requirement to obtain a title V permit under section 502(a). 
Based upon this determination, we are proposing to require that any 
sterilization facility subject to subpart O obtain a title V permit 
from the delegated authority in which the source is located. 
Corresponding revision is proposed to the General Provisions table 
entry for 40 CFR 63.1(c)(2) to remove the comment discussing the 
exemption of area sources from the obligation to obtain a title V 
operating permit. The additional public participation and compliance 
benefits of additional informational, monitoring, reporting, 
certification, and enforcement requirements that exist in title V 
should be required for these sources. These additional requirements are 
important to ensure that these sources are maintaining compliance with 
the requirements of this rule. While there is additional burden 
associated with title V permitting on the affected facilities, this 
burden is not significant compared to the expected benefits to public 
health and compliance.\67\ We estimate that approximately 86 affected 
area sources will be required to obtain title V permits. The EPA 
solicits comment on the requirement for area sources in the source 
category to obtain a title V permit (Comment C-74).
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    \67\ EPA believes that more involvement from local permitting 
authorities and the public will result in requirements that properly 
address the health needs and concerns of individual communities. A 
benefit in a title V permit is increased transparency and public 
participation, so that members of affected communities can know 
where sources are, what they are emitting, and the standards they 
are subject to, as well as having an opportunity to participate in 
the process. title V permits also generally include specific 
monitoring, recordkeeping, and reporting requirements that allow for 
greater transparency and assurance of sources' compliance with 
standards.
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c. Definitions
    We are proposing the addition, revision, and deletion of numerous 
terms in the regulatory text, which is provided as part of this 
rulemaking. Specifically, we are proposing to add terms for:
     Emission process units and sources (combination 
sterilizer, EtO dispensing, Group 1 room air emission, Group 2 room air 
emissions, indoor EtO storage, pre-aeration handling of sterilized 
material, post-aeration handling of sterilized material, vacuum pump 
operation),
     Emissions capture (natural draft opening, PTE),
     APCDs and related terminology (acid-water scrubber, 
catalytic oxidizer, gas/solid reactor, peak shaver, residence time),
     Monitoring (continuous monitor, maximum daily mass of EtO 
charged to the sterilization chamber(s), maximum scrubber liquor pH, 
minimum room air EtO concentration, minimum temperature at the inlet to 
the catalyst bed, minimum temperature difference across the catalyst 
bed, minimum temperature in or immediately downstream of the firebox, 
minimum stack volumetric flow rate, rolling average), and
     Others (aeration, single-item sterilization).
    It should be noted that while aeration is a defined process, there 
is still off-gassing of EtO from sterilized product that occurs after 
aeration (and before if a combination sterilizer is not used). We 
solicit comment on these new definitions (Comment C-75). We are also 
proposing to revise existing definitions in the regulatory text.
     Adding acronyms and alternative terms to the definitions 
for aeration room vent, chamber exhaust vent, and sterilization chamber 
vent,
     Replacing ``at least 99-percent control of ethylene oxide 
emissions'' with ``the appropriate control of EtO emissions'' in the 
definitions for

[[Page 22852]]

maximum ethylene glycol concentration and maximum liquor tank level,
     Clarifying the definition for aeration room to indicate 
that if a facility uses only combination sterilizers, there are no 
aeration rooms at the facility,
     Revising the definition for sterilization facility to 
clarify that facilities that engage in single-item sterilization are 
included in this definition, and
     Broadening the definition for sterilization operation to 
include times when EtO is stored within the building, EtO is dispensed 
from a container to a chamber, when material is moved from 
sterilization to aeration, or when materials are handled post-aeration.
    We solicit comment on these revised definitions (Comment C-76). 
Finally, we are proposing to delete the following definitions from the 
regulatory text:
     Baseline temperature.
     Compliance date.
     Effective date.
     Manifolding emissions.
     Source(s) using less than 1 ton.
     Source(s) using 1 ton.
     Source(s) using 1 to 10 tons.
     Source(s) using less than 10 tons.
     Source(s) using 10 tons.
    We are proposing to remove the definition for baseline temperature 
because the proposed operating limits for oxidizers depend on the type 
of oxidizer being used, and we believe it is best to provide 
definitions for individual operating limits, like what is done for 
acid-water scrubbers. We are also proposing to remove the definitions 
for compliance date and effective date because the definitions are 
already provided in the General Provisions. Because we are proposing 
detailed requirements for combined emissions streams, we are proposing 
to remove the definition for manifolding emissions. Finally, we are 
proposing to remove the definitions for source(s) using less than 1 
ton, source(s) using 1 ton, source(s) using 1 to 10 tons, source(s) 
using less than 10 tons, and source(s) using 10 tons because these 
terms are not descriptive enough (i.e., they do not specify the 
duration of use). We solicit comment on the removal of these 
definitions (Comment C-77).
d. Standards for Combined Emissions Streams
    The EPA's understanding of control configurations at commercial 
sterilization facilities has changed since the rule was promulgated in 
1994. In recent years, companies have implemented a wide variety of 
combinations when controlling emission streams at these facilities. As 
a result, it can be difficult to determine whether one vent type is in 
compliance with the rule when it is being combined with other vent 
types. Therefore, the EPA is proposing to structure the rule 
requirements so that facilities can combine emission streams based on 
the best approach for their facilities. The EPA is proposing different 
emission limitations based on the format of the standard (i.e., removal 
efficiency or emission rate) with which the facility is complying. If 
complying with a removal efficiency standard, the EPA is proposing that 
the facility must comply with the removal efficiency standard for the 
emission source in the composite stream that has the most stringent 
removal efficiency. For example, at a facility where EtO use is at 
least 10 tpy, a combined stream that consists of emissions from ARVs 
subject to a removal efficiency of 99.5 percent and CEVs subject to a 
removal of 96 percent would be subject to a removal efficiency standard 
of 99.5 percent removal efficiency for the combined emission stream. If 
complying with an emission rate standard, the EPA is proposing that the 
facility must comply with an emission rate standard that is equal to 
the sum of the emission rate standards for each emission source type in 
the composite stream. For example, at a facility where EtO use is at 
least 10 tpy, a combined stream that consists of emissions from ARVs 
subject to an EtO emission rate of 7.0E-3 lb/hr and CEVs subject to an 
EtO emission rate of 3.4E-3 lb/hr must comply with an EtO emission rate 
standard of less than 1.0E-2 lb/hr from the combined emission stream. 
This approach is necessary because of the multiple configurations of 
emissions streams, and results in standards that are equivalent and 
equally protective compared to the standards for individual emissions 
streams. When determining compliance, it is important for facilities to 
understand how their emission streams are configured and what the 
ultimate emissions from these streams are. The EPA solicits comment on 
the proposed standards for combined emissions streams (Comment C-78).
e. Negative Pressure for SCVs and CEVs
    The current subpart O rule does not include capture requirements 
for emissions. For ARVs and room air emissions, we are proposing PTE 
requirements to ensure complete capture of EtO from these sources. It 
is also important to ensure that emissions from other sources such as 
SCV and CEV are completely captured and routed to control systems. The 
EPA is proposing to require that emissions from SCVs and CEVs be routed 
under negative pressure when ducted to a control system. The EPA 
solicits comment on this proposed requirement (Comment C-79).

H. What compliance dates are we proposing, and what is the rationale 
for the proposed compliance dates?

    Amendments to the subpart O NESHAP proposed in this rulemaking for 
adoption under CAA sections 112(d)(2), (3), (5), and (6), as well as 
CAA section 112(f)(2), are subject to the compliance deadlines outlined 
in the CAA under section 112(i).
    For the requirements we are proposing under CAA sections 112(d)(2)-
(3), (d)(5), and (d)(6), we are proposing all existing affected sources 
must comply with all amendments no later than 18 months after the 
effective date of the final rule. In addition, we are proposing all new 
affected sources must comply with all amendments upon startup. For 
existing sources, CAA section 112(i) provides that the compliance date 
shall be as expeditious as practicable, but no later than 3 years after 
the effective date of the standard. (``Section 112(i)(3)'s three-year 
maximum compliance period applies generally to any emission standard . 
. . promulgated under [section 112].'' Association of Battery Recyclers 
v. EPA, 716 F.3d 667, 672 (D.C. Cir. 2013)). In determining what 
compliance period is as expeditious as practicable, we consider the 
amount of time needed to plan and construct projects and change 
operating procedures. As provided in CAA section 112(i), all new 
affected sources would be required to comply with these requirements by 
the effective date of the final amendments to the subpart O standards 
or startup, whichever is later.
    We are proposing updated operating and monitoring requirements for 
capture and control systems. We anticipate that these requirements 
would require the installation of monitoring equipment, and we project 
most commercial sterilization facilities would install additional or 
replacement systems to monitor and adjust process variables that impact 
the parameters being monitored. Like the addition of control equipment, 
these monitoring requirements for capture and control systems would 
require engineering evaluations, solicitation and review of vendor 
quotes, contracting and installation of the equipment, and operator 
training. Installation of additional or replacement systems to monitor 
and adjust process variables may require the capture and control 
system(s) to be taken out of service and may also require a significant 
portion of

[[Page 22853]]

the commercial sterilization facility to be shutdown. Therefore, we are 
proposing that it is necessary to provide 18 months after the effective 
date of the final rule (or upon startup, whichever is later) for 
facilities to comply with the updated operating and monitoring 
requirements for capture and control systems.
    Additionally, as previously discussed in this preamble, we are 
proposing under CAA section 112(f), provisions for SCVs, ARVs, CEVs, 
and room air emissions at certain groups of facilities. The proposed 
provisions may require additional time to plan, purchase, and install 
equipment for capture and control. For example, for SCVs at facilities 
where EtO use is at least 40 tpy, if the affected source cannot 
demonstrate 99.94 percent control of EtO emissions, then a new control 
system will need to be installed. Therefore, we are proposing a 
compliance date of 18 months after the effective date of the final 
rule. For all new affected sources that commenced construction or 
reconstruction after April 13, 2023, we are proposing facilities comply 
with the requirements that are being proposed upon startup.
    Finally, we are proposing to change the requirements for SSM by 
removing the exemption from the requirements to meet the standards 
during SSM periods. We are also proposing electronic reporting 
requirements. We are positing that facilities would need some time to 
successfully accomplish these revisions, including time 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, including making adjustments to standard operating 
procedures, and to convert reporting mechanisms to install necessary 
hardware and software. The EPA recognizes the confusion that multiple 
different compliance dates for individual requirements would create and 
the additional burden such an assortment of dates would impose. From 
our assessment of the timeframe needed for compliance with the entirety 
of the proposed revisions to SSM requirements as well as the new 
proposed electronic reporting requirements for compliance reports and 
performance evaluation reports, the EPA considers a period of 18 months 
after the effective date of the final rule to be the most expeditious 
compliance period practicable and, thus, is proposing that all affected 
sources be in compliance with these revised SSM and electronic 
reporting requirements upon initial startup or within 18 months of the 
effective date of the final rule, whichever is later. However, we are 
proposing to provide 60 days after the effective date of the final rule 
(or upon startup, whichever is later) for facilities to comply with the 
requirement to report performance test and evaluation results, notices 
of compliance status, and initial and ongoing compliance reports 
electronically. There are several factors that either support or 
undermine the justification for an expedited compliance timeframe for 
existing sources. We are aware that, in order to implement the capture 
and emission reduction systems necessary to comply with the 
requirements that we are proposing, facilities will need to cease 
operations for a certain period of time in order to implement these 
systems. However, an expedited compliance timeframe could result in 
more facilities needing to cease operations simultaneously. This means 
that increased coordination would be needed to ensure that the supply 
of medical devices is not adversely impacted. We also recognize the 
health risks that this source category currently poses and that the 
risks of EtO exposure have been made known to the public for some time. 
In addition, a significant portion of the industry is already operating 
the types of capture and control systems that we anticipate will be 
needed to comply with the proposed standards. We solicit comment on the 
appropriate compliance timeframe for existing sources. To aid in our 
decision-making, we solicit comment on the amount of time that a 
facility would need to comply with the proposed standards, as well as 
the amount of time the facility would need to cease EtO sterilization 
operations (either fully or partially) and how this may impact the 
medical device supply chain. (Comment C-80).

IV. Summary of Cost, Environmental, and Economic Impacts

A. What are the affected sources?

    There are 86 facilities in the Commercial Sterilization Facilities 
source category that are currently operating.\68\ A complete list of 
facilities that are currently subject to the NESHAP is available in 
Appendix 1 of the Risk and Technology Review memorandum, which is 
available in the docket for this rulemaking. We anticipate that an 
additional 2 facilities will commence operation and become subject to 
the rule in the next 3 years.
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    \68\ As discussed in section III.C.1, the risk assessment was 
conducted on these 86 facilities, as well as 11 research and 
development facilities, for a total of 97 facilities. To exercise 
caution, we included research facilities in our assessment because 
there is a lack of certainty over whether these are true research 
facilities, for which CAA section 112(c)(7) requires that a separate 
category be established.
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B. What are the air quality impacts?

    For the standards that we are proposing, we estimated an EtO 
emissions reduction of 19 tpy for the total source category reductions 
from sterilizer chambers, aeration rooms, chamber exhaust, and room air 
emission sources. See the Technology Review memorandum.

C. What are the cost impacts?

    The nationwide costs of the proposed amendments are presented in 
Table 1 of this preamble. As described in this preamble, we are 
proposing to reduce EtO emissions from SCV, CEV, ARV, Group 1 room air, 
and Group 2 room air emission sources. The capital costs, for 
facilities with controls already in place, include addition of add-on 
dry scrubber controls to meet the emission reduction determined under 
the technology review; ductwork; an interlock system, damper, and in-
chamber EtO concentration monitor for the CEV; and performance testing. 
The capital costs also include a PTE, an add-on dry scrubber control 
device, pressure monitoring device, and performance testing for room 
air emission sources. Annual costs include annualized capital costs, 
media replacement cost, operating and maintenance labor, recordkeeping 
and reporting, electricity, and taxes and insurance. The total annual 
costs of the proposed rule are estimated to be $68 million in 2021 
dollars.

D. What are the economic impacts?

    The present value (PV) of the estimated compliance costs from 2023 
to 2042 for the proposed option is $640 million in 2021 dollars, 
discounted at a 7 percent rate. The equivalent annualized value (EAV) 
of the costs for the proposed rule is $74 million, using a 7 percent 
discount rate. Using a 3 percent discount rate, the PV and EAV of the 
cost impacts are estimated to be $784 million and $53 million, 
respectively.
    The EPA conducted economic impact analyses for this proposal, as 
detailed in the document Regulatory Impact Analysis for the Proposed 
National Emission Standards for Hazardous Air Pollutants: Ethylene 
Oxide Commercial Sterilization and Fumigation Operations, which is 
available in the docket for this action. For the proposed amendments, 
the EPA performed a screening analysis which compared facility-level 
annualized compliance

[[Page 22854]]

costs to annual revenues of the ultimate owner of the facility (or 
facilities), known as the ultimate parent company. These cost-to sales 
ratios underpin the ``sales test'' methodology the EPA uses to assess 
small business impacts for a rulemaking.
    There are 88 facilities affected by the proposed amendments and 
they are owned by 48 ultimate parent companies.\69\ Of these 88 
facilities, 24 facilities, or 27 percent, are owned by 20 small 
entities at the ultimate parent company level. We calculated the cost-
to-sales ratios for all the affected parent companies to assess the 
magnitude of the costs of the proposed amendments and determine whether 
there is potential for significant impacts on small entities. For all 
firms, the average cost-to-sales ratio is approximately 7.9 percent; 
the median cost-to-sales ratio is approximately 0.3 percent; and the 
maximum cost-to-sales ratio is approximately 68 percent. For large 
firms, the average cost-to-sales ratio is approximately 0.3 percent; 
the median cost to-sales ratio is approximately 0.03 percent; and the 
maximum cost-to-sales ratio is approximately 3.9 percent. For small 
entities, the average cost-to-sales ratio is approximately 19 percent; 
the median cost to-sales ratio is approximately 7.3 percent; and the 
maximum cost-to-sales ratio is approximately 68 percent. Large firms 
incur most of the total costs estimated for the proposed rule and they 
incur higher total annual costs per firm on average than small firms. 
However, when estimated costs are examined relative to revenues, large 
firms are much less affected by the proposed rule than small firms.
---------------------------------------------------------------------------

    \69\ This includes the 86 facilities that are currently 
operating, as well as two planned facilities that are expected to 
start operating before the proposed compliance deadline.
---------------------------------------------------------------------------

    Under the proposed amendments, 17 out of 20 (85 percent) parent 
companies identified as small entities are estimated to incur total 
annual costs greater than 1 percent of annual revenues. Additionally, 
12 out of 20 small entities (60 percent) are estimated to incur 
annualized costs greater than 3 percent of annual revenues. The 12 
small entities with cost-to-sales ratios of 3 percent or greater 
collectively own 16 facilities.
    The EtO sterilization industry is an integral part of the supply 
chain for many medical devices and capacity constraints have been 
reported. As described in section I.A.1 of this preamble, we have been 
engaged with FDA regarding the potential impacts of this proposal on 
commercial sterilization facilities that play a key role in the 
availability of certain medical devices. Based on the data we analyzed/
considered, we project that the largest impacts are limited to a 
handful of companies, and many of them are already in the planning 
stage for additional controls. We believe large firms account for a 
large percentage of the output of this industry, and they appear much 
less affected by the proposed rule than small firms when examining 
costs relative to revenues. See the Regulatory Impact Analysis for 
further detail on the cost estimates, small entity impact analysis, and 
a discussion of potential market and economic impacts.

E. What are the benefits?

    The EPA did not monetize the benefits from the estimated emission 
reductions of HAP associated with this proposed action. This does not 
imply that there are no benefits associated with the EtO emission 
reductions estimated for this proposed rule. We expect this proposed 
action would provide benefits associated with lower risk of adverse 
health effects (e.g., cancer incidence) in communities near facilities 
subject to the NESHAP.

V. Request for Comments

    We solicit comments on this proposed action. In addition to general 
comments on this proposed action, we are also interested in additional 
data that may improve the analyses. We are specifically interested in 
receiving any information regarding developments in practices, 
processes, and control technologies that reduce EtO emissions. In 
addition, we solicit comment on several aspects of the requirements 
herein, including the true effectiveness of these requirements on 
reducing EtO emissions, any capital and annual costs that we did not 
account for, the time that is needed to comply with requirements, and 
any other potential barriers to or impacts of imposing these 
requirements.

VI. Incorporation by Reference (IBR)

    We are proposing to incorporate by reference ISO 11135--
Sterilization of health-care products--Ethylene oxide--Requirements for 
the development, validation and routine control of a sterilization 
process for medical devices (Approved July 25, 2014), as part of a GACT 
management practice standard for existing Group 2 room air emissions at 
area source facilities where EtO use is less than 20 tpy (proposed to 
be IBR approved for Table 5 to 40 CFR part 63, subpart O). This ISO 
standard ``describes requirements that, if met, will provide an EtO 
sterilization process intended to sterilize medical devices, which has 
appropriate microbicidal activity''. We are also proposing to 
incorporate by reference ISO 11138-1--Sterilization of health care 
products--Biological indicators--Part 1: General requirements (Approved 
March 2017), as part of a GACT management practice standard for 
existing Group 2 room air emissions at area source facilities where EtO 
use is less than 20 tpy (proposed to be IBR approved for Table 5 to 40 
CFR part 63, subpart O). This ISO standard ``specifies general 
requirements for production, labelling, test methods and performance 
requirements for the manufacture of biological indicators including 
inoculated carriers and suspensions intended for use in validation and 
monitoring of sterilization processes''. Compliance with the 
requirements ensures that validations conducted following this 
International Standard will provide products that meet the defined 
requirements for sterile products with a high degree of confidence. We 
are proposing to require certain facilities to follow either the Cycle 
Calculation Approach or the Bioburden/Biological Indicator Approach to 
achieve sterility assurance in accordance with ISO 11135:2014 and ISO 
11138-1:2017, which will result in lower EtO emissions throughout the 
facility. In addition, we are proposing to incorporate by reference ISO 
17025--General requirements for the competence of testing and 
calibration laboratories (Approved November 2017). This ISO standard 
``contains requirements for laboratories to enable them to demonstrate 
they operate competently and are able to generate valid results''. The 
ISO standards are available from the International Organization for 
Standardization, Chemin de Blandonnet 8, CP 401, 1214 Vernier, Geneva, 
Switzerland. See https://www.iso.org.

VII. Statutory and Executive Order Reviews

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

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

    This action is a significant regulatory action under section 
3(f)(1) of Executive Order 12866 that was submitted to OMB for review 
because it may adversely affect in a material way the economy, a sector 
of the economy, productivity,

[[Page 22855]]

competition, jobs, the environment, public health or safety, or state, 
local, or tribal governments. Any changes made in response to OMB 
recommendations have been documented in the docket. The EPA prepared an 
analysis of the potential economic impacts and benefits associated with 
this action. This analysis, Regulatory Impact Analysis for the Proposed 
National Emission Standards for Hazardous Air Pollutants: Ethylene 
Oxide Commercial Sterilization and Fumigation Operations, is available 
in the docket for this rulemaking.

B. 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 1666.12. You can find a copy of the ICR in the 
docket for this rulemaking, and it is briefly summarized here.
    We are proposing amendments that change the reporting and 
recordkeeping requirements for several emission sources at commercial 
sterilization facilities (e.g., SCV, ARV, CEV, and room air emissions). 
The proposed amendments also require electronic reporting, removes the 
SSM exemption, and imposes other revisions that affect reporting and 
recordkeeping. This information would be collected to assure compliance 
with 40 CFR part 63, subpart O.
    Respondents/affected entities: Owners or operators of commercial 
sterilization facilities.
    Respondent's obligation to respond: Mandatory (40 CFR part 63, 
subpart O).
    Estimated number of respondents: 86 facilities.
    Frequency of response: Quarterly, semiannual, or annual. Responses 
include notification of compliance status reports and semiannual 
compliance reports.
    Total estimated burden: 34,351 hours (per year) for the responding 
facilities and 9,174 hours (per year) for the Agency. Burden is defined 
at 5 CFR 1320.3(b).
    Total estimated cost: $5,140,563 (per year), which includes 
$2,549,368 annualized capital and operation and maintenance costs for 
the responding facilities.
    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 [email protected], Attention: Desk Officer for the 
EPA. Since OMB is required to make a decision concerning the ICR 
between 30 and 60 days after receipt, OMB must receive comments no 
later than May 15, 2023. The EPA will respond to any ICR-related 
comments in the final rule.

C. Regulatory Flexibility Act (RFA)

    Pursuant to section 603 of the RFA, EPA prepared an initial 
regulatory flexibility analysis (IRFA) that examines the impact of the 
proposed rule on small entities along with regulatory alternatives that 
could minimize the impact. The complete IRFA is available in section 
5.2 of the regulatory impact assessment (RIA) in the docket and is 
summarized here.
    As discussed in section II.A., 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.). The EPA is proposing to revise the NESHAP for 
Commercial Sterilization Facilities by both amending existing standards 
and establishing additional standards for this source category, 
exercising authority under multiple provisions of section 112 of the 
CAA.
    For purposes of assessing the impacts of this rule on small 
entities, a small entity is defined as a small business in the 
commercial EtO sterilization industry whose parent company has revenues 
or numbers of employees below the Small Business Administration (SBA) 
Size Standards for the relevant NAICS code. We have identified 20 
different NAICS codes within this source category. A complete list of 
those NAICS codes and SBA Size Standards is available in section 5.2 of 
the RIA. The proposed rule contains provisions that would affect 
approximately 20 small entities. These small entities are involved in 
sterilizing various types of medical devices and spices. In addition, 
at least eight of these small entities are involved in sterilizing the 
types of medical devices discussed in section I.A.1 of this preamble. 
Under the proposed rule requirements, small entities would be required 
to comply with various emission standards, which may require the use of 
a new control device. Some small entities would also be required to 
comply with a BMP, which would require them to re-validate some or all 
of their sterilization cycles if they are not already in compliance. 
Small entities would also need to demonstrate compliance with the 
emission standards through periodic performance testing and parametric 
monitoring or through the use of an EtO CEMS. This proposed rule 
includes reporting, recordkeeping, and other administrative 
requirements. Under the proposed rule, EPA estimates that approximately 
12 small entities (60 percent of small entities) could incur total 
annual costs associated with the proposal that are at least three 
percent of their annual revenues. Considering the level of total annual 
costs relative to annual sales for these small entities, EPA determined 
that there is potential for the proposed requirements to have a 
`Significant Impact on a Substantial Number of Small Entities' 
(SISNOSE). See section 5.2 of the RIA for more information on the 
characterization of the impacts under the proposed rule.
    As required by section 609(b) of the RFA, EPA also convened a Small 
Business Advocacy Review (SBAR) Panel to obtain advice and 
recommendations from small entity representatives (SERs) that 
potentially would be subject to the rule's requirements. On December 
10, 2020, EPA's Small Business Advocacy Chairperson convened the Panel, 
which consisted of the Chairperson, the Director of the Sector Policies 
and Programs Division within EPA's Office of Air Quality Planning and 
Standards, the Administrator of the Office of Information and 
Regulatory Affairs within OMB, and the Chief Counsel for Advocacy of 
the Small Business Administration (SBA).
    Prior to convening the Panel, EPA conducted outreach and solicited 
comments from the SERs. After the Panel was convened, the Panel 
provided additional information to the SERs and requested their input. 
In light of the SERs' comments, the Panel considered the regulatory 
flexibility issues and elements of the IRFA specified by RFA/Small 
Business Regulatory Enforcement and Fairness Act (SBREFA) and developed 
the findings and discussion summarized in the SBAR report. The SBAR 
Panel recommended several flexibilities relating to the format of the 
standards, room air emissions requirements, subcategorization, the 
compliance timeframe, the consideration of GACT standards, 
incentivizing lower EtO use, a compliance alternative for combined 
emission streams, proximity requirements, and the consideration of 
interactions with OSHA standards. EPA

[[Page 22856]]

is including some of these flexibilities as a part of the proposed rule 
requirements and soliciting comment on others that may be considered 
for the final rule. The report was finalized on April 26, 2021, and 
transmitted to the EPA Administrator for consideration. A copy of the 
full SBAR Panel Report is available in the rulemaking docket.

D. 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.

E. 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.

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

    This action does not have tribal implications as specified in 
Executive Order 13175. None of the commercial sterilization facilities 
that have been identified as being affected by this action are owned or 
operated by tribal governments or located within tribal lands. Thus, 
Executive Order 13175 does not apply to this action.

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

    Executive Order 13045 (62 FR 19885, April 23, 1997) directs Federal 
agencies to include an evaluation of the health and safety effects of 
the planned regulation on children in Federal health and safety 
standards and explain why the regulation is preferable to potentially 
effective and reasonable feasible alternatives. This action is subject 
to Executive Order 13045 because it is an economically significant 
regulatory action as defined by Executive Order 12866, and the EPA 
believes that the environmental health or safety risk addressed by this 
action has a disproportionate effect on children. The EPA's Policy on 
Children's Health \70\ also applies to this action. Accordingly, we 
have evaluated the environmental health or safety effects of EtO 
emissions and exposures on children. The protection offered by these 
standards may be especially important for children.
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    \70\ Children's Health Policy available at: https://www.epa.gov/children/childrens-health-policy-and-plan.
---------------------------------------------------------------------------

    Because EtO is mutagenic (i.e., it can damage DNA), children are 
expected to be more susceptible to its harmful effects. To take this 
into account, as part of the risk assessment in support of this 
rulemaking, the EPA follow its guidelines \71\ and applied age-
dependent adjustment factors (ADAFs) for childhood exposures (from 
birth up to 16 years of age). With the ADAF applied to account for 
greater susceptibility of children, the adjusted EtO inhalation URE is 
5 x 10-3 per [micro]g/m\3\. It should be noted that, because EtO is 
mutagenic, emission reductions proposed in this preamble will be 
particularly beneficial to children.
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    \71\ U.S. EPA. 2005. Supplemental Guidance for Assessing 
Susceptibility from Early-Life Exposure to Carcinogens. U.S. 
Environmental Protection Agency, Washington, DC, EPA/630/R-03/003F. 
https://www.epa.gov/sites/default/files/2013-09/documents/childrens_supplement_final.pdf.
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    More detailed information on the evaluation of the scientific 
evidence and policy considerations pertaining to children, including an 
explanation for why the Administrator judges the proposed standards to 
be requisite to protect public health, including the health of 
children, with an adequate margin of safety, in addition to the 
summaries of this action's health and risk assessments are contained in 
sections II.E and G and sections III.C and D of this preamble and 
further documented in the risk report, Residual Risk Assessment for the 
Commercial Sterilization Facilities Source Category in Support of the 
2022 Risk and Technology Review Proposed Rule, which is available in 
Docket ID No. EPA-HQ-OAR-2019-0178.

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

    This action is not a ``significant energy action'' because it is 
not likely to have a significant adverse effect on the supply, 
distribution, or use of energy. The overall energy impact of this 
proposed rule should be minimal for commercial sterilization facilities 
and their parent companies. EPA was unable to quantify the degree to 
which manufacturers would need to switch sites, so we cannot estimate 
potential energy impacts related to transportation. EPA solicits 
comment on any potential impacts the proposed standards may have in 
relation to energy use for transportation (Comment C-81).

I. National Technology Transfer and Advancement Act (NTTAA) and 1 CFR 
Part 51

    This action involves technical standards. Therefore, the EPA 
conducted searches for the EtO Commercial Sterilization NESHAP through 
the Enhanced National Standards Systems Network (NSSN) Database managed 
by the American National Standards Institute (ANSI). We also contacted 
voluntary consensus standards (VCS) organizations and accessed and 
searched their databases. We conducted searches for EPA Methods 204 of 
40 CFR part 51, appendix M; EPA Methods 1, 1, 2, 2A, 2C, and 3B of 40 
CFR part 60, appendix A; and EPA Method 320 of 40 CFR part 63, appendix 
A. During the EPA's VCS search, if the title or abstract (if provided) 
of the VCS described technical sampling and analytical procedures that 
are similar to the EPA's reference method, the EPA considered it as a 
potential equivalent method. We reviewed all potential standards to 
determine the practicality of the VCS for this rule. The EPA may 
reconsider determinations of impracticality when additional information 
is available for particular VCS.
    No applicable VCS were identified for EPA Methods 204, 1, 1, 2, 2A, 
and 2C. The following VCS were identified as acceptable alternatives to 
the EPA test methods for the purpose of this rule.
    The EPA proposes to use the VCS ANSI/ASME PTC 19.10-1981 Part 10 
(2010), ``Flue and Exhaust Gas Analyses,'' as an acceptable alternative 
to EPA Method 3B for the manual procedures only and not the 
instrumental procedures. The ANSI/ASME PTC 19.10-1981-Part 10 method 
incorporates both manual and instrumental methodologies for the 
determination of oxygen content. The manual method segment of the 
oxygen determination is performed through the absorption of oxygen. The 
EPA is not proposing to incorporate this VCS by reference. This method 
is available both in the docket for this rulemaking and at the American 
National Standards Institute (ANSI), 1899 L Street NW, 11th floor, 
Washington, DC 20036 and the American Society of Mechanical Engineers 
(ASME), Three Park Avenue, New York, NY 10016-5990. See https://www.ansi.org and https://www.asme.org.
    In addition, the EPA proposes to use the VCS ASTM D6348-12e1, 
``Determination of Gaseous Compounds by Extractive Direct Interface 
Fourier Transform (FTIR) Spectroscopy,'' as an acceptable alternative 
to EPA Method

[[Page 22857]]

320 of appendix A to 40 CFR part 63 with caveats requiring inclusion of 
selected annexes to the standard as mandatory. The ASTM D6348-12e1 
method is an extractive FTIR spectroscopy-based field test method and 
is used to quantify gas phase concentrations of multiple target 
compounds in emission streams from stationary sources. The EPA is not 
proposing to incorporate this VCS by reference. We are proposing the 
test plan preparation and implementation in the Annexes to ASTM D 6348-
03, Sections Al through A8 are mandatory; and in ASTM D6348-03 Annex A5 
(Analyte Spiking Technique), the percent (%) R must be determined for 
each target analyte (Equation A5.5). We are proposing that in order for 
the test data to be acceptable for a compound, %R must be 70% < R <= 
130%. If the %R value does not meet this criterion for a target 
compound, the test data are not acceptable for that compound and the 
test must be repeated for that analyte (i.e., the sampling and/or 
analytical procedure should be adjusted before a retest). We are 
proposing that the %R value for each compound be reported in the test 
report, and all field measurements be corrected with the calculated %R 
value for that compound by using the following equation:
[GRAPHIC] [TIFF OMITTED] TP13AP23.112

    The ASTM D6348-12e1 method is available both in the docket for this 
rulemaking and at ASTM International, 1850 M Street NW, Suite 1030, 
Washington, DC 20036. See https://www.astm.org/.
    In this rule, the EPA is proposing regulatory text for Tables 1 
through 5 to 40 CFR part 63, subpart O, that includes IBR in accordance 
with requirements of 1 CFR 51.5. Specifically, the EPA is incorporating 
by reference ISO 11135:2014. The ISO standards are available from the 
International Organization for Standardization, Chemin de Blandonnet 8, 
CP 401, 1214 Vernier, Geneva, Switzerland. See https://www.iso.org.
    The EPA welcomes comments on this aspect of the proposed rulemaking 
and, specifically, invites the public to identify potentially 
applicable VCS, and to explain why the EPA should use such standards in 
this regulation (Comment C-82).

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

    Executive Order 12898 (59 FR 7629, February 16, 1994) directs 
Federal agencies, to the greatest extent practicable and permitted by 
law, to make environmental justice part of their mission by identifying 
and addressing, as appropriate, disproportionately high and adverse 
human health or environmental effects of their programs, policies, and 
activities on minority populations (people of color and/or indigenous 
peoples) and low-income populations.
    The EPA believes that the human health or environmental conditions 
that exist prior to this action result in or have the potential to 
result in disproportionate and adverse human health or environmental 
effects on people of color, low-income populations and/or indigenous 
peoples. A total of 19.4 million people live within 10 km of the 97 
facilities that were assessed. The percent of the population that is 
Hispanic or Latino is substantially higher than the national average 
(34 percent versus 19 percent), driven by the seven facilities in 
Puerto Rico, where an average of 99 percent of the 658,000 people 
living within 10 km of the facilities are Hispanic or Latino. The 
proportion of other demographic groups living within 10 km of 
commercial sterilizers is similar to the national average. The EPA also 
conducted a risk assessment of possible cancer risks and other adverse 
health effects, and found that prior to this proposed regulation, 
cancer risks were above acceptable levels for several areas in which 
these demographic groups live. See section III.E for an analysis that 
characterizes populations living in proximity of facilities and risks 
prior to the proposed regulation.
    The EPA believes that this action is likely to reduce existing 
disproportionate and adverse effects on people of color, low-income 
populations and/or indigenous peoples. This action proposed to 
establish standards for SCVs, ARVs, and CEVs at facilities where EtO 
use is less than 1 tpy, ARVs and CEVs at facilities where EtO use is at 
least 1 tpy but less than 10 tpy, CEVs at facilities where EtO use is 
at least 10 tpy, and room air emissions. In addition, it proposes to 
tighten standards for SCVs at facilities where EtO use is at least 1 
tpy, as well as ARVs at facilities where EtO use is at least 10 tpy. 
This action also proposes amendments to correct and clarify regulatory 
provisions related to emissions during periods of SSM, including 
removing general exemptions for periods of SSM and adding work practice 
standards for periods of SSM where appropriate. As a result of these 
proposed changes, we expect zero people to be exposed to risk levels 
above 100-in-1 million. See sections III.B and III.D for more 
information about the control requirements of the regulation and the 
resulting reduction in cancer risks.
    The EPA additionally identified and addressed environmental justice 
concerns by engaging in outreach activities to communities we expect to 
be impacted most by the rulemaking.\72\ The EPA is also proposing that 
owners and operators of commercial sterilization facilities submit 
electronic copies of required compliance reports, performance test 
reports, and performance evaluation reports, which will provide greater 
access to information for impacted communities.
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    \72\ https://www.epa.gov/newsreleases/epa-launches-community-engagement-efforts-new-ethylene-oxide-risk-information.
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    The information supporting this Executive order review is contained 
in section III.E of this preamble, as well as in a technical report, 
Analysis of Demographic Factors for Populations Living Near Ethylene 
Oxide Commercial Sterilization and Fumigation Operations, available in 
the docket for this action.

List of Subjects in 40 CFR Part 63

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

Michael S. Regan,
Administrator.
[FR Doc. 2023-06676 Filed 4-12-23; 8:45 am]
BILLING CODE 6560-50-P