[Federal Register Volume 89, Number 67 (Friday, April 5, 2024)]
[Rules and Regulations]
[Pages 24090-24203]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-05905]



[[Page 24089]]

Vol. 89

Friday,

No. 67

April 5, 2024

Part II





Environmental Protection Agency





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40 CFR Parts 60 and 63





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

  Federal Register / Vol. 89 , No. 67 / Friday, April 5, 2024 / Rules 
and Regulations  

[[Page 24090]]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 60 and 63

[EPA-HQ-OAR-2019-0178; FRL-7055-02-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: Final rule.

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SUMMARY: This action finalizes the residual risk and technology review 
(RTR) conducted for the Commercial Sterilization Facilities source 
category regulated under national emission standards for hazardous air 
pollutants (NESHAP) under the Clean Air Act. The EPA is finalizing 
decisions concerning the RTR, including definitions for affected 
sources, emission standards for previously unregulated sources, 
amendments pursuant to the risk review to address ethylene oxide (EtO) 
emissions from certain sterilization chamber vents (SCVs), aeration 
room vents (ARVs), chamber exhaust vents (CEVs), and room air 
emissions, and amendments pursuant to the technology review for certain 
SCVs and ARVs. In addition, we are taking final action to correct and 
clarify regulatory provisions related to emissions during periods of 
startup, shutdown, and malfunction (SSM), including removing exemptions 
for periods of SSM. We are also taking final action to require owners 
and operators to demonstrate compliance through the use of EtO 
continuous emissions monitoring systems (CEMS), with exceptions for 
very small users of EtO; add provisions for electronic reporting of 
performance test results and other reports; and include other technical 
revisions to improve consistency and clarity. We estimate that these 
final amendments will reduce EtO emissions from this source category by 
approximately 21 tons per year (tpy).

DATES: This final rule is effective on April 5, 2024. The incorporation 
by reference (IBR) of certain material listed in the rule is approved 
by the Director of the Federal Register April 5, 2024. The 
incorporation by reference (IBR) of certain other material listed in 
the rule was approved by the Director of the Federal Register before 
February 27, 2021.

ADDRESSES: The U.S. Environmental Protection Agency (EPA) has 
established a docket for this action under Docket ID No. EPA-HQ-OAR-
2019-0178. All documents in the docket are listed on the https://www.regulations.gov/ website. Although listed, some information is not 
publicly available, e.g., Confidential Business Information 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 form. Publicly 
available docket materials are available either electronically through 
https://www.regulations.gov/, or in hard copy at the EPA Docket Center, 
WJC West Building, Room Number 3334, 1301 Constitution Ave. NW, 
Washington, DC. The Public Reading Room hours of operation are 8:30 
a.m. to 4:30 p.m. Eastern Standard Time (EST), Monday through Friday. 
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.

FOR FURTHER INFORMATION CONTACT: For questions about this final action, 
contact U.S. EPA, Attn: Jonathan Witt, Mail Drop: E143-05, 109 T.W. 
Alexander Drive, P.O. Box 12055, RTP, North Carolina 27711; telephone 
number: (919) 541-5645; and email address: [email protected]. For 
specific information regarding the risk modeling methodology, contact 
U.S. EPA, Attn: Matthew Woody, Mail Drop: C539-02, 109 T.W. Alexander 
Drive, P.O. Box 12055, RTP, North Carolina 27711; telephone number: 
(919) 541-1535; and email address: [email protected].

SUPPLEMENTARY INFORMATION: 
    Preamble acronyms and abbreviations. We use multiple acronyms and 
terms in this preamble. While this list may not be exhaustive, to ease 
the reading of this preamble and for reference purposes, the EPA 
defines the following terms and acronyms here:

ADAF age-dependent adjustment factor
AEGL acute exposure guideline level
APCD air pollution control device
ARV aeration room vent
ASME American Society of Mechanical Engineers
BTF Beyond-the-Floor
BMP best management practice
CAA Clean Air Act
CDX Central Data Exchange
CEDRI Compliance and Emissions Data Reporting Interface
CEMS continuous emission 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
ERT Electronic Reporting Tool
EtO ethylene oxide
FDA Food and Drug Administration
FIFRA Federal Insecticide, Fungicide, and Rodenticide Act
FR Federal Register
FRFA final regulatory flexibility analysis
FTIR Fourier Transform Infrared Spectroscopy
GACT generally available control technology
HAP hazardous air pollutants(s)
HEM Human Exposure Model
HQ hazard quotient
ICR Information Collection Request
ID Interim Decision
IFU instructions for use
IRFA initial regulatory flexibility analysis
IRIS Integrated Risk Information System
ISO International Organization for Standardization
km kilometer
lb pound
lb/h pounds per hour
LEL lower explosive limit
LPL lower prediction 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
NESHAP national emission standards for hazardous air pollutants
OMB Office of Management and Budget
OPP Office of Pesticide Programs
OSHA Occupational Safety and Health Administration
PID Proposed Interim Decision
ppbv parts per billion by volume
ppm parts per million
ppmv parts per million by volume
PTE permanent total enclosure
REL reference exposure level
RDL Representative detection level
RFA Regulatory Flexibility Act
RIA regulatory impact assessment
RTR risk and technology review
SAB Science Advisory Board
SBA Small Business Administration
SBAR Small Business Advocacy Review
SCV sterilization chamber vent
SER small entity representative
SSM startup, shutdown, and malfunction
TOSHI target organ-specific hazard index
tpy tons per year
UPL upper prediction limit
[micro]g/m\3\ micrograms per cubic meter
UMRA Unfunded Mandates Reform Act
URE unit risk estimate
VCS voluntary consensus standards

    Background information. On April 13, 2023, the EPA proposed 
revisions to the Commercial Sterilization Facilities NESHAP based on 
our RTR. In this action, we are finalizing decisions and revisions for 
the rule. We summarize some of the more significant comments we timely 
received regarding the proposed rule and provide our responses in this 
preamble. A summary of all other public comments on the proposal and 
the EPA's responses to

[[Page 24091]]

those comments is available in Summary of Public Comments and Responses 
for the Risk and Technology Review for Commercial Sterilization 
Facilities, Docket ID No. EPA-HQ-OAR-2019-0178. A ``track changes'' 
version of the regulatory language that incorporates the changes in 
this action is available in the docket.
    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?
    D. Judicial Review and Administrative Reconsideration
II. Background
    A. What is the statutory authority for this action?
    B. What is the Commercial Sterilization Facilities source 
category and how does the NESHAP regulate HAP emissions from the 
source category?
    C. What changes did we propose for the Commercial Sterilization 
Facilities source category in our April 13, 2023, RTR proposal?
III. What is included in this final rule?
    A. What are the final rule amendments addressing the affected 
source definitions?
    B. What are the final rule amendments pursuant to CAA sections 
112(d)(2), 112(d)(3), and 112(d)(5) for the Commercial Sterilization 
Facilities source category?
    C. What are the final rule amendments based on the risk review 
for the Commercial Sterilization Facilities source category?
    D. What are the final rule amendments based on the technology 
review for the Commercial Sterilization Facilities source category?
    E. What are the final rule amendments addressing emissions 
during periods of startup, shutdown, and malfunction?
    F. What other changes have been made to the NESHAP?
    G. What are the effective and compliance dates of the standards?
IV. What is the rationale for our final decisions and amendments for 
the Commercial Sterilization Facilities source category?
    A. Amendments Addressing the Affected Source Definitions
    B. Amendments Pursuant to CAA sections 112(d)(2), 112(d)(3), and 
112(d)(5) for the Commercial Sterilization Facilities Source 
Category
    C. Residual Risk Review for the Commercial Sterilization 
Facilities Source Category
    D. Technology Review for the Commercial Sterilization Facilities 
Source Category
    E. Amendments Addressing Emissions During Periods of SSM
    F. Other Amendments to the Standards
V. Summary of Cost, Environmental, and Economic Impacts and 
Additional Analyses Conducted
    A. What are the affected facilities?
    B. What are the air quality impacts?
    C. What are the cost impacts?
    D. What are the economic impacts?
    E. What are the benefits?
    F. What analysis of environmental justice did we conduct?
VI. Statutory and Executive Order Reviews
    A. Executive Orders 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 and Executive Order 14096: Revitalizing Our Nation's 
Commitment to Environmental Justice for All
    K. Congressional Review Act (CRA)

I. General Information

A. Executive Summary

1. Purpose of the Regulatory Action
    Exercising authority under multiple provisions of section 112 of 
the Clean Air Act (CAA), we are finalizing revisions to the NESHAP for 
Commercial Sterilization Facilities (40 CFR part 63, subpart O) by both 
amending the current standards and establishing standards for 
previously unregulated emissions within this source category. First, we 
are finalizing emission standards under CAA sections 112(d)(2)-(3) and 
(d)(5) for previously unregulated emission sources of EtO. Second, we 
are finalizing risk-based standards under CAA section 112(f)(2) to 
protect public health with an ample margin of safety. Third, we are 
finalizing emission standards under CAA section 112(d)(6) based on our 
review of developments in practices, processes, and control 
technologies for this source category.
    This final rulemaking reflects the EtO toxicological assessment 
that EPA's Integrated Risk Information System (IRIS) Program completed 
in December 2016,\1\ which indicated that EtO is a far more potent 
carcinogen than we had understood when the RTR for this source category 
was conducted in 2006. There are 88 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. We 
have determined that approximately 23 of these facilities pose high 
lifetime cancer risks to the surrounding communities, and some 
facilities pose exceptionally high risks that are among some of the 
highest for a CAA section 112(f)(2) risk assessment. Throughout this 
rulemaking process, we have engaged in outreach activities to these 
communities, along with their State and local governments, to discuss 
their concerns, along with the need and potential solutions for 
reducing emissions and increasing transparency on exposure and 
potential impacts to communities, which this final rule will achieve.
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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 will reduce EtO emissions and lifetime cancer 
risks in multiple communities across the country, including communities 
with EJ concerns, and it updates our standards using proven and cost-
effective control technologies that are already in use at some 
facilities in this source category. The protections offered by these 
standards will be especially important for children. In addition, this 
rule will advance the President's Cancer Moonshot,\2\ by preventing 
cancer before it starts. Recognizing that we now have additional 
information about the health risks of EtO that was not available at the 
time of the 2006 RTR, and in order to ensure that our standards for 
this source category adequately protect public health, we have 
conducted a second residual risk review under CAA section 112(f)(2), as 
discussed in section I.A.3 of this preamble.
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    \2\ https://www.whitehouse.gov/briefing-room/statements-releases/2023/09/13/fact-sheet-as-part-of-president-bidens-unity-agenda-white-house-cancer-moonshot-announces-new-actions-and-commitments-to-end-cancer-as-we-know-it/.
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    In deciding to conduct this second residual risk review, we 
considered the health effects of EtO exposure, the impacts to 
surrounding communities, 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. While commercial sterilizers provide a critical benefit 
for the health of all, protecting people who live near commercial 
sterilization facilities from the disproportionate risk of being 
significantly harmed by toxic air

[[Page 24092]]

pollution is also a core responsibility for the EPA under the CAA.
    At the same time, we recognize that commercial sterilization 
facilities play a vital role in maintaining an adequate supply of 
sterilized medical devices for public health needs in the U.S. 
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.'' \3\ In developing this final rule, 
therefore, we carefully considered 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 device supply chain.
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    \3\ https://www.fda.gov/medical-devices/general-hospital-devices-and-supplies/sterilization-medical-devices.
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    To ensure our 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 final rulemaking. This has enabled us to work 
from the best possible information when conducting the analyses to 
support this final 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 
final rule on commercial facilities that sterilize medical devices. 
These discussions have focused on identifying and discussing any 
concerns regarding the potential impact on the availability of certain 
medical devices that are sterilized with EtO, in cases where 
alternative sterilization methods are not readily available, in 
particular, devices that are (1) experiencing or at risk of 
experiencing a shortage, (2) intended to provide life-supporting, life-
sustaining care or that is intended for use in emergency medical care 
or during surgery, (3) used in pediatric services, and/or (4) 
sterilized exclusively at a particular facility.
    Mindful of the vital role that commercial sterilizers play in 
supplying the nation with sterile medical devices, and the core 
objective of protecting public health under CAA section 112, the EPA 
has carefully evaluated the feasibility and cost of compliance with 
this rule, and potential implications for the medical device supply 
chain.\4\ The EPA notes that a number of the facilities covered by this 
final rule have already implemented one or more of the controls that 
will be needed for compliance. Moreover, the EPA's own experience 
working with facility owners, as well as State and local agencies that 
have regulated EtO emissions from these facilities, confirms that it is 
feasible for individual facilities to install the required controls 
well within the deadlines provided in this rule, and for multiple 
facilities to do so simultaneously.
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    \4\ For more information, see the document Regulatory Impact 
Analysis for the Final National Emission Standards for Hazardous Air 
Pollutants: Ethylene Oxide Commercial Sterilization and Fumigation 
Operations, available in the docket for this rulemaking.
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    In addition, as a result of the comments received, as well as the 
EPA's consultation with FDA and other Federal partners, the final rule 
incorporates several key changes from the proposed rule, including 
modifications to the format of certain standards and compliance 
flexibilities. We are also providing sufficient compliance time to 
enable these facilities to continue sterilizing products while 
installing and testing new control systems and associated equipment 
that will afford ample protection for nearby communities. These 
modifications to the proposed rule are intended to facilitate cost-
effective compliance, and to avoid any impacts to the integrity of the 
medical device supply chain, while ensuring that these standards reduce 
cancer risks for communities exposed to EtO emissions.
    Given that key industry players are already planning for 
compliance, and in light of the significant changes made between the 
proposal and this final rule, the EPA does not anticipate that the 
implementation of these standards will have any adverse impacts on the 
medical supply chain. However, as the Agency proceeds to implement this 
final rule, we intend to continue to work closely with FDA, the 
relevant trade associations, and facility owners to monitor the process 
of planning for compliance, to proactively identify any anticipated 
changes in facility operations that might implicate the medical supply 
chain, and to take appropriate steps to address any such impacts. In 
addition, in order to increase the resilience of the medical supply 
chain, we support the development and implementation of viable, safe, 
and cost-effective alternatives to EtO sterilization.
    On April 13, 2023, the Office of Pesticide Programs (OPP) published 
a notice announcing the availability of a proposed interim decision 
(PID) as part of its periodic review of the registration of EtO under 
the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) (88 FR 
22447). The PID contained a number of measures aimed at protecting 
workers from excessive EtO exposure. Since the issuance of the PID, OPP 
has been actively collaborating with the Office of Air and Radiation to 
ensure that the requirements of the FIFRA Interim Decision (ID) do not 
interfere with the requirements of this rule, and vice versa. The ID 
will contain the final requirements to mitigate worker exposure to EtO, 
considering the comments received on the PID. Furthermore, OPP has been 
consulting regularly with other Federal agencies and with industry 
trade groups, to discuss how best to harmonize the requirements of the 
FIFRA ID with the requirements of this rule, and to ensure that the 
operative standards, once finalized, will protect both workers and 
neighboring communities from the risks of EtO exposure while mitigating 
and managing any risk to the supply chain for sterile medical devices.
2. Summary of the Major Provisions of the Regulatory Action in Question
    We are finalizing 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 also 
finalizing 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.\5\
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    \5\ In 1992, pursuant to CAA section 112(c)(1), we published a 
list of major and area sources for regulation under CAA section 112, 
including major and area sources at commercial sterilization 
facilities. 57 FR 31576, 31586 (July 16, 1992). Area sources at 
commercial sterilization facilities were listed for regulation under 
CAA section 112(c)(3) based on our finding that they present 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.
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    For the following, previously unregulated emission sources at 
commercial sterilization facilities, we are setting standards under CAA 
sections 112(d)(2)-(3) or (d)(5): SCVs and ARVs at facilities where EtO 
use is less than 1 tpy,\6\ ARVs at facilities where

[[Page 24093]]

EtO use is at least 1 tpy but less than 10 tpy,\7\ CEVs,\8\ and room 
air emissions.\9\
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    \6\ In developing the original rule, EPA considered potential 
standards for SCV and ARV at area source facilities where EtO use is 
less than 1 tpy but the Agency understood these sources at the time 
to have low emission contributions (e.g., a facility with EtO use of 
1,999 lb/yr would have roughly less than 167 lb/month of usage and 
emissions, and less than 41 lb/week usage and emissions.) At the 
time, EPA considered costs for monitoring, recordkeeping, and 
reporting under the rule. Threshold cutoffs for area sources are at 
the discretion of the Agency.
    \7\ EPA considered standards for ARV and CEV at area source 
facilities where EtO use is at least 1 tpy and less than 10 tpy. As 
noted, the Agency understood at the time that the largest emission 
source of EtO occurred from the SCV, and therefore finalized 
emission reduction standards for all SCV at facilities where EtO use 
is at least 1 tpy. At the time ARV sources were understood to have 
low emission contributions. As noted, threshold cutoffs for area 
sources are at the discretion of the Agency.
    \8\ The standards for CEVs were originally promulgated on 
December 6, 1994. Following promulgation of the rule, we 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. We 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). However, as discussed in section 
III.B.5 of the proposal preamble (88 FR 22790), facilities with 
controlled CEVs have revised their operating procedures to address 
the explosion issue by not exceeding 10 to 25 percent of the LEL. We 
have, therefore, determined that CEVs can be safely controlled.
    \9\ As discussed in section III.A, 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 our assessment of the residual risk after 
considering the emission reductions from the previous standards in 
subpart O, as well as the standards under CAA sections 112(d)(2)-(3) or 
(d)(5) for the previously unregulated sources, we are finalizing more 
stringent standards under CAA section 112(f)(2) to address risk at the 
following types of sources:

 SCVs at facilities where EtO use is at least 30 tpy
 SCVs at facilities where EtO use is at least 10 tpy but less 
than 30 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 30 tpy
 CEVs at area source facilities \10\ where EtO use is at least 
400 tpy
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    \10\ As discussed in section III.B of the proposal preamble (88 
FR 22790, April 13, 2023), CAA section 112(a) defines a major source 
as ``any stationary source or group of stationary sources located 
within a contiguous area and under 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 has taken a 
restriction so that its potential to emit is less than the threshold 
amounts for major sources. Most of the EtO used at these facilities 
is released through SCVs and ARVs, and subpart O contains emission 
standards for these 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 for these facilities, it is our understanding that 
all facilities that use more than 10 tpy are synthetic area sources.
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 CEVs at area source facilities where EtO use is at least 60 
but less than 400 tpy
 Group 1 room air emissions \11\ at area source facilities 
where EtO use is at least 40 tpy
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    \11\ As discussed in section III.A, Group 1 room air emissions 
cover indoor EtO storage, EtO dispensing, vacuum pump operation, and 
pre-aeration handling of sterilized material.
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 Group 2 room air emissions \12\ at area source facilities 
where EtO use is at least 20 tpy
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    \12\ As discussed in section III.A, Group 2 room air emissions 
cover post-aeration handling of sterilized material.
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 Group 2 room air emissions at area source facilities where EtO 
use is at least 4 tpy but less than 20 tpy

    Finally, under CAA section 112(d)(6), we are revising current 
standards for the following sources that were regulated in the previous 
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

    Table 1 summarizes the final CAA section 112(d) and 112(f)(2) 
standards.

  Table 1--Summary of Standards After Taking Actions Pursuant to CAA Sections 112(d)(2), 112(d)(3), 112(d)(5),
                                            112(f)(2), and 112(d)(6)
----------------------------------------------------------------------------------------------------------------
         Emission source           Existing or new?         EtO use            Standards          CAA section
----------------------------------------------------------------------------------------------------------------
SCV.............................  Existing and new..  At least 30 tpy...  99.99 percent       112(f)(2).
                                                                           emission
                                                                           reduction.
                                                      At least 10 tpy     99.9 percent        112(f)(2).
                                                       but less than 30    emission
                                                       tpy.                reduction.
                                                      At least 10 tpy...  99.9 percent        112(d)(6).
                                                                           emission
                                                                           reduction.
                                                      At least 1 but      99.8 percent        112(f)(2) and
                                                       less than 10 tpy.   emission            112(d)(6).
                                                                           reduction.
                                                      Less than 1 tpy...  99 percent          112(d)(5).
                                                                           emission
                                                                           reduction.
ARV.............................  Existing..........  At least 30 tpy...  99.9 percent        112(f)(2).
                                                                           emission
                                                                           reduction.
                                                      At least 10 tpy     99.6 percent        112(f)(2).
                                                       but less than 30    emission
                                                       tpy.                reduction.
                                                      At least 10 tpy...  99.6 percent        112(d)(6).
                                                                           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 30 tpy...  99.9 percent        112(f)(2).
                                                                           emission
                                                                           reduction.
                                                      At least 10 tpy...  99.9 percent        112(d)(6).
                                                                           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.
CEVs at major source facilities.  Existing and new..  N/A...............  99.94 percent       112(d)(2) and
                                                                           emission            112(d)(3).
                                                                           reduction \1\.
CEVs at area source facilities..  Existing and new..  At least 400 tpy..  99.9 percent        112(f)(2).
                                                                           emission
                                                                           reduction.
                                                      At least 60 but     99.9 percent        112(f)(2).
                                                       less than 400 tpy.  emission
                                                                           reduction.
                                                      Less than 60 tpy..  99 percent          112(d)(5).
                                                                           emission
                                                                           reduction.
Group 1 room air emissions at     Existing and new..  N/A...............  97 percent          112(d)(2) and
 major sources.                                                            emission            112(d)(3).
                                                                           reduction 2 3.
Group 1 room air emissions at     Existing and new..  At least 40 tpy...  98 percent          112(f)(2).
 area sources.                                                             emission
                                                                           reduction \3\.
                                                      Less than 40 tpy..  80 percent          112(d)(5).
                                                                           emission
                                                                           reduction \3\.

[[Page 24094]]

 
Group 2 room air emissions at     Existing and new..  N/A...............  86 percent          112(d)(2) and
 major sources.                                                            emission            112(d)(3).
                                                                           reduction 1 3.
Group 2 room air emissions at     Existing..........  At least 20 tpy...  98 percent          112(f)(2).
 area sources.                                                             emission
                                                                           reduction \3\.
                                                      At least 4 but      80 percent          112(f)(2).
                                                       less than 20 tpy.   emission
                                                                           reduction \3\.
                                                      Less than 4 tpy...  Lower the EtO       112(d)(5).
                                                                           concentration
                                                                           within each
                                                                           sterilization
                                                                           chamber to 1 ppm
                                                                           before the
                                                                           chamber can be
                                                                           opened \4\.
                                  New...............  At least 20 tpy...  98 percent          112(f)(2).
                                                                           emission
                                                                           reduction \3\.
                                                      At least 4 but      80 percent          112(f)(2).
                                                       less than 20 tpy.   emission
                                                                           reduction \3\.
                                                      Less than 4 tpy...  80 percent          112(d)(5).
                                                                           emission
                                                                           reduction \3\.
----------------------------------------------------------------------------------------------------------------
\1\ MACT floor.
\2\ Beyond-the-Floor (BTF) standard.
\3\ To assure compliance with the emission limit, we are requiring each facility to operate area sources with
  these emissions in accordance with the PTE requirements of EPA Method 204 of appendix M to 40 CFR part 51.
\4\ Owners and operators may also apply for an alternative means of emission limitation under CAA section
  112(h)(3).

    To demonstrate compliance with the emission limits, we are 
finalizing capture requirements. We are also finalizing a requirement 
for facilities to monitor with an EtO continuous emissions monitoring 
system (CEMS), with exceptions for small users.
3. EPA Authority
    We note that the EPA 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 our discretion or authority to conduct another risk review 
should we consider that such review is warranted. As discussed in more 
detail in section IV.C of this preamble, as our understanding of the 
health effects of EtO developed, we conducted a second residual risk 
review under CAA section 112(f)(2) for commercial sterilization 
facilities using EtO in order to ensure that the standards provide an 
ample margin of safety to protect public health.
    As discussed in further detail in section IV.C, this second 
residual risk review also encompasses certain area sources for which we 
did not evaluate residual risk in our 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, 
we 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 our discretion under CAA 
section 112(f)(5) not to do a CAA section 112(f)(2) analysis for those 
emission points for which GACT standards were established (67 FR 
17715). However, as we 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 IRIS cancer unit risk 
estimate (URE) for EtO, which is approximately 60 times greater than 
the value we used in our previous risk assessment, we are now 
exercising our discretionary authority to conduct another CAA section 
112(f)(2) analysis and to include in this analysis area source 
commercial sterilizers using EtO for which we have promulgated, or have 
considered, GACT standards.
    Section 112(d)(6) of the CAA requires EPA to review and revise, as 
necessary, standards promulgated under CAA section 112 at least every 
eight years, taking into account developments in practices, processes, 
and control technologies. We last completed this required technology 
review for the Ethylene Oxide Commercial Sterilization NESHAP (40 CFR 
63, subpart O) in 2006. Accordingly, in this final action, we are also 
conducting a CAA section 112(d)(6) review of the current standards in 
this source category.
4. Costs and Benefits
    Table 2 of this preamble summarizes the costs of this final action 
for 40 CFR part 63, subpart O (Ethylene Oxide Commercial Sterilization 
NESHAP).

                             Table 2--Total Capital Investment and Total Annual Cost
                                                     [2021$]
----------------------------------------------------------------------------------------------------------------
                                                                   Number of
                                                              facilities w/costs   Total capital   Total annual
                         Requirement                            associated with     investment         costs
                                                               new  requirements
----------------------------------------------------------------------------------------------------------------
Permanent total enclosure...................................                  28     $77,500,000      $8,280,000
Additional control devices..................................                  83     187,000,000      43,000,000
Monitoring and testing......................................                  89      48,100,000      19,400,000
Recordkeeping and reporting.................................              \1\ 90  ..............   \2\ 2,600,000
                                                             ---------------------------------------------------
    Total...................................................              \1\ 90     313,000,000      74,000,000
----------------------------------------------------------------------------------------------------------------
\1\ This includes the 88 facilities that are currently operating, as well as two planned facilities that are
  expected to start operating within the next few years.
\2\ This includes $763,000 of one-time annual costs for reading the rule and developing record systems.


[[Page 24095]]

    The capital costs for permanent total enclosure (PTE) and 
additional gas/solid reactors were annualized to 20 years. We estimate 
that these amendments will reduce EtO emissions from this source 
category by 21 tpy. Table 3 of this preamble summarizes the cancer risk 
reductions that will result from the final amendments, which are 
updated based on revisions made in the final rule and described in more 
detail in section IV.C.2.

                                   Table 3--Summary of Cancer Risk Reductions
----------------------------------------------------------------------------------------------------------------
                                                                                            Cancer risks after
                                        Current cancer risks--   Current cancer risks--  implementation of final
                                           actual emissions       allowable emissions           amendments
----------------------------------------------------------------------------------------------------------------
Maximum Individual Risk (MIR) \1\....  6,000-in-1 million.....  8,000-in-1 million \3\.  100-in-1 million.
Number of People with Cancer Risks     19,000.................  260,000................  0.
 >100-in-1 million.
Number of People with Cancer Risks     8.5 million............  62 million.............  700,000 to 1.4
 >=1-in-1 million.                                                                        million.\2\
Estimated Annual Cancer Incidence      0.9....................  8......................  0.1 to 0.2.\2\
 (cases per year).
----------------------------------------------------------------------------------------------------------------
\1\ The MIR or maximum individual lifetime cancer risk is defined as the increase in estimated cancer risk
  associated with a 70-year lifetime of continuous exposure at the highest concentration of HAP where people are
  likely to live.
\2\ Ranges in values account for if all facilities were performing at the level of the standards (high end) to
  considering facilities that are currently performing better than the standards (low end).

    As indicated in table 3, we project that the standards in the final 
rule will significantly reduce incremental lifetime cancer risks 
associated with emissions of EtO from this source category. We estimate 
that the current maximum increase in lifetime cancer risk associated 
with any facility in this source category is 6,000-in-1 million based 
on estimated actual emissions (or 8,000-in-1 million based on allowable 
emissions) under the existing standards, and that approximately 19,000 
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 our presumptive upper bound threshold for acceptable 
health risks), based on actual emissions. When considering allowable 
emissions, this number increases to 260,000. Under the final rule, no 
individual will 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 will be reduced by approximately 92 percent.
    See section V of this preamble for further discussion of the costs 
and a discussion of the benefits of the final standards. See section 
IV.F of this preamble for discussion of the revisions to monitoring, 
recordkeeping, reporting, and testing requirements. See section IV.C 
for a discussion of the risk assessment results.

B. Does this action apply to me?

    Regulated entities. Categories and entities potentially regulated 
by this action are shown in table 4 of this preamble.

 Table 4--NESHAP and Industrial Source Categories Affected by This Final
                                 Action
------------------------------------------------------------------------
        Industrial category                NESHAP         NAICS \1\ code
------------------------------------------------------------------------
Surgical and Medical Instrument     40 CFR part 63,               339112
 Manufacturing.                      subpart O.
Surgical Appliance and Supplies     40 CFR part 63,               339113
 Manufacturing.                      subpart O.
Pharmaceutical Preparation          40 CFR part 63,               325412
 Manufacturing.                      subpart O.
Spice and Extract Manufacturing...  40 CFR part 63,               311942
                                     subpart O.
Dried and Dehydrated Food           40 CFR part 63,               311423
 Manufacturing.                      subpart O.
Packaging and Labeling Services...  40 CFR part 63,               561910
                                     subpart O.
------------------------------------------------------------------------
\1\ North American Industry Classification System.

    Table 4 of this preamble is not intended to be exhaustive, but 
rather to provide a guide for readers regarding entities likely to be 
affected by the final action for the source category listed. To 
determine whether your facility is affected, you should examine the 
applicability criteria in the appropriate NESHAP. If you have any 
questions regarding the applicability of any aspect of this NESHAP, 
please contact the appropriate person listed in the preceding FOR 
FURTHER INFORMATION CONTACT section of this preamble.

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 final action will also be available on the internet. Following 
signature by the EPA Administrator, the EPA will post a copy of this 
final action at: https://www.epa.gov/stationary-sources-air-pollution/ethylene-oxide-emissions-standards-sterilization-facilities. Following 
publication in the Federal Register, the EPA will post the Federal 
Register version and key technical documents at this same website.
    Additional information is available on the RTR website at https://www.epa.gov/stationary-sources-air-pollution/risk-and-technology-review-national-emissions-standards-hazardous. This information 
includes an overview of the RTR program and links to project websites 
for the RTR source categories.

D. Judicial Review and Administrative Reconsideration

    Under Clean Air Act (CAA) section 307(b)(1), judicial review of 
this final action is available only by filing a petition for review in 
the United States Court of Appeals for the District of Columbia Circuit 
(the Court) by June 4, 2024. Under CAA section 307(b)(2), the 
requirements established by this final rule may not be challenged 
separately in any civil or criminal proceedings brought by the EPA to 
enforce the requirements.
    Section 307(d)(7)(B) of the CAA further provides that only an 
objection to a rule or procedure which was raised with reasonable 
specificity during the period for public comment (including any public 
hearing) may be raised

[[Page 24096]]

during judicial review. This section also provides a mechanism for the 
EPA to reconsider the rule if the person raising an objection can 
demonstrate to the Administrator that it was impracticable to raise 
such objection within the period for public comment or if the grounds 
for such objection arose after the period for public comment (but 
within the time specified for judicial review) and if such objection is 
of central relevance to the outcome of the rule. Any person seeking to 
make such a demonstration should submit a Petition for Reconsideration 
to the Office of the Administrator, U.S. EPA, Room 3000, WJC South 
Building, 1200 Pennsylvania Ave. NW, Washington, DC 20460, with a copy 
to both the person(s) listed in the preceding FOR FURTHER INFORMATION 
CONTACT section, and the Associate General Counsel for the Air and 
Radiation Law Office, Office of General Counsel (Mail Code 2344A), U.S. 
EPA, 1200 Pennsylvania Ave. NW, Washington, DC 20460.

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.). The discussion that follows identifies the 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. Section 112 of the CAA establishes a two-stage regulatory 
process to address emissions of hazardous air pollutants (HAP) from 
stationary sources. In the first stage, we must identify categories of 
sources emitting one or more of the HAP listed in CAA section 112(b) 
and then promulgate technology-based NESHAP for those sources. 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, any single HAP at a rate of 10 
tons per year (tpy) or more, or 25 tpy or more of any combination of 
HAP. All other sources are ``area sources.'' For major sources, these 
standards are commonly referred to as maximum achievable control 
technology (MACT) standards and must reflect the maximum degree of 
emission reductions of HAP achievable (after considering cost, energy 
requirements, and non-air quality health and environmental impacts). In 
developing MACT standards, CAA section 112(d)(2) directs the EPA to 
consider the application of measures, processes, methods, systems, or 
techniques, including, but not limited to, those that reduce the volume 
of or eliminate HAP emissions through process changes, substitution of 
materials, or other modifications; enclose systems or processes to 
eliminate emissions; collect, capture, or treat HAP when released from 
a process, stack, storage, or fugitive emissions point; are design, 
equipment, work practice, or operational standards; or any combination 
of the above.
    For these MACT standards, the statute specifies certain minimum 
stringency requirements, which are referred to as MACT floor 
requirements, and which may not be based on cost considerations. See 
CAA section 112(d)(3). For new sources, the MACT floor cannot be less 
stringent than the emission control achieved in practice by the best-
controlled similar source. The MACT standards for existing sources can 
be less stringent than floors for new sources, but they cannot be less 
stringent than the average emission limitation achieved by the best-
performing 12 percent of existing sources in the category or 
subcategory (or the best-performing five sources for categories or 
subcategories with fewer than 30 sources). In developing MACT 
standards, we must also consider control options that are more 
stringent than the floor under CAA section 112(d)(2). We may establish 
standards more stringent than the floor, based on the consideration of 
the cost of achieving the emissions reductions, any non-air quality 
health and environmental impacts, and energy requirements. 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 the 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 discretion.
    In the second stage of the regulatory process, the CAA requires the 
EPA to undertake two different analyses, which we refer to as the 
technology review and the residual risk review. Under the technology 
review, we must review the technology-based standards and revise them 
``as necessary (taking into account developments in practices, 
processes, and control technologies)'' no less frequently than every 8 
years, pursuant to CAA section 112(d)(6). In conducting this 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 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).
    The residual risk review in the second stage of the regulatory 
process 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

[[Page 24097]]

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) 
\13\ 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. For 
more information on the statutory authority for this rule, see 88 FR 
22790, April 13, 2023.
---------------------------------------------------------------------------

    \13\ Although defined as ``maximum individual risk,'' MIR refers 
only to cancer risk and reflects the estimated risk if an individual 
were exposed to the maximum level of a pollutant for a 70-year 
lifetime.
---------------------------------------------------------------------------

B. What is the Commercial Sterilization Facilities source category and 
how does the NESHAP regulate HAP emissions from the source category?

    The EPA promulgated the EtO Commercial Sterilization Facilities 
NESHAP on December 6, 1994 (59 FR 62585). The standards are codified at 
40 CFR part 63, subpart O. The EtO commercial sterilization industry 
consists of facilities operating a sterilizer process that uses EtO to 
sterilize or fumigate materials (e.g., medical equipment and supplies, 
spices, and other miscellaneous products and items). The source 
category covered by this MACT standard currently includes 88 
facilities.
    The original 1994 rulemaking for this source category set standards 
for EtO emissions originating from three emission points: sterilization 
chamber vents (SCV), aeration room vents (ARV), and chamber exhaust 
vents (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 EtO residuals desorbing from sterilized products 
within the facility, but the current EtO Commercial Sterilization 
NESHAP does not include standards for room air emissions.
    In the chamber EtO sterilization process, 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 EtO residuals 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.
    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.
    In 2006, we 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 current emission standards for commercial sterilization 
facilities in 40 CFR part 63, subpart O are shown in table 5:

                            Table 5--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.


[[Page 24098]]

    For more information on the commercial sterilization industry and 
the current standards under 40 CFR part 63, subpart O, see 88 FR 22790, 
April 13, 2023.
    We note that hospital sterilizers are regulated under a different 
NESHAP (40 CFR part 63, subpart WWWWW), which is not addressed in this 
rulemaking.\14\ We are aware of the potential risk posed by EtO 
emissions from this source category and will address hospital 
sterilizers in a future rulemaking.
---------------------------------------------------------------------------

    \14\ 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 changes did we propose for the Commercial Sterilization 
Facilities source category in our April 13, 2023, RTR proposal?

    On April 13, 2023, the EPA published a proposed rule in the Federal 
Register for the EtO Commercial Sterilization NESHAP, 40 CFR part 63, 
subpart O, that took into consideration the RTR analyses. In the 
proposed rule, we proposed emission standards under CAA sections 
112(d)(2)-(3) or (d)(5) for a number of unregulated emission sources of 
EtO. We then proposed tightening certain of these proposed standards 
and existing standards with risk-based standards under CAA section 
112(f)(2) in order to protect public health with an ample margin of 
safety. Finally, we proposed revisions to certain existing standards 
under CAA section 112(d)(6) based on our review of developments in 
practices, processes, and control technologies for this source 
category.
    For the following emission sources that were unregulated, we 
proposed to set standards under CAA sections 112(d)(2)-(3) or (d)(5):
     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.
    Next, based on our assessment of the residual risk after 
considering the emission reductions from the standards in subpart O, as 
well as the proposed standards for the unregulated sources, we proposed 
more stringent standards under CAA section 112(f)(2) to address risk 
for the following types of sources:
     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, and
     Group 2 room air emissions at area source facilities where 
EtO use is at least 20 tpy.
    Finally, under CAA section 112(d)(6), we proposed to revise 
standards for the following sources that were regulated in the previous 
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, and
     ARVs at facilities where EtO use is at least 10 tpy.
    Table 6 summarizes the proposed section CAA section 112(d) and 
112(f)(2) standards.

 Table 6--Summary of Standards After Proposed Actions Pursuant to CAA Sections 112(d)(2), 112(d)(3), 112(d)(5),
                                            112(f)(2), and 112(d)(6)
----------------------------------------------------------------------------------------------------------------
         Emission source           Existing or new?         EtO use            Standards          CAA section
----------------------------------------------------------------------------------------------------------------
SCV.............................  Existing and 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 10 tpy...  99.94 percent       112(d)(6).
                                                                           emission
                                                                           reduction.
                                                      At least 1 but      99.8 percent        112(f)(2) and
                                                       less than 10 tpy.   emission            112(d)(6).
                                                                           reduction.
                                                      Less than 1 tpy...  99 percent          112(d)(5).
                                                                           emission
                                                                           reduction.
ARV.............................  Existing..........  At least 10 tpy...  99.6 percent        112(d)(6).
                                                                           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...  99.9 percent        112(d)(6).
                                                                           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.
CEV.............................  Existing and new..  At least 10 tpy...  3.2E-4 lb/h.......  112(d)(2) and (3).
                                                      At least 1 but      99.9 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......  Existing and new..  N/A...............  1.3E-3 lb/h \1\...  112(d)(2) and
                                                                                               112(d)(3).
Group 1 room air emissions at     Existing and new..  N/A...............  1.3E-3 lb/h \1\...  112(d)(5).
 area sources.
Group 2 room air emissions at     Existing and new..  N/A...............  2.8E-3 lb/h \1\...  112(d)(2) and
 major sources.                                                                                112(d)(3).
Group 2 room air emissions at     Existing..........  At least 20 tpy...  2.8E-3 lb/h \1\...  112(f)(2).
 area sources.                                        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).

[[Page 24099]]

 
                                  New...............  N/A...............  2.8E-3 lb/h \1\...  112(d)(5).
----------------------------------------------------------------------------------------------------------------
\1\ To assure compliance with the emission limit, we proposed requiring 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.

    To demonstrate compliance with the emission limits, we proposed 
capture requirements. We also proposed that facilities either monitor 
with an EtO CEMS or conduct initial and annual performance tests with 
continuous parameter monitoring.
    We also proposed the following amendments:
     Corrections and clarifications to 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.
     Revisions to monitoring and performance testing 
requirements and addition of provisions for electronic reporting of 
performance test results and reports, performance evaluation reports, 
and compliance reports.
     Requiring all area source facilities to obtain a title V 
operating permit, and
     Compliance requirements for facilities using combined 
emission streams.

III. What is included in this final rule?

    This action finalizes the EPA's determinations pursuant to the RTR 
provisions of CAA section 112 for the Commercial Sterilization 
Facilities source category and amends the EtO Commercial Sterilization 
NESHAP based on those determinations. This action also finalizes other 
changes to the NESHAP, including adding requirements and clarifications 
for periods of SSM; requiring the use of CEMS to demonstrate compliance 
for facilities where EtO use is at least 100 pounds (lb)/year; adding 
provisions for electronic reporting of performance test results and 
reports, performance evaluation reports, and compliance reports; and 
other minor editorial and technical changes. This action also reflects 
several changes to the April 2023 proposal in consideration of comments 
received during the public comment period described in section IV of 
this preamble.

A. What are the final rule amendments addressing the affected source 
definitions?

    The previous subpart O did not contain definitions for affected 
sources, which meant that the definition of an ``affected source'' at 
40 CFR 63.2 applied.\15\ We did not believe that this was appropriate 
because a facility may not route all emissions from a particular type 
of point source to the same control system, thus making compliance 
demonstration with the standards difficult. For SCVs, ARVs, and CEVs, 
we are finalizing, as proposed, the affected source definition as the 
individual vent. For Group 1 and Group 2 room air emissions, we are 
finalizing, as proposed, the affected source definition as the 
collection of all room air emissions for each group at any 
sterilization facility. Group 1 room air emissions are defined as 
emissions from indoor EtO storage, EtO dispensing, vacuum pump 
operations, and pre-aeration handling of sterilized material. Group 2 
room air emissions are defined as emissions from post-aeration handling 
of sterilized material.
---------------------------------------------------------------------------

    \15\ 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.''
---------------------------------------------------------------------------

    Section IV.A.3 of this preamble provides a summary of key comments 
we received on the affected source definitions and our responses.

B. What are the final rule amendments pursuant to CAA sections 
112(d)(2), 112(d)(3), and 112(d)(5) for the Commercial Sterilization 
Facilities source category?

    We are finalizing EtO emissions standards pursuant to CAA sections 
112(d)(2)-(3) and 112(d)(5) for major and area sources that were 
previously unregulated. Please note that the final standards for some 
of these sources are further tightened pursuant to CAA section 
112(f)(2), as shown in table 1 in section I.A above and discussed in 
more detail below in sections III.C and IV.\16\
---------------------------------------------------------------------------

    \16\ These sources include CEVs at area source facilities where 
EtO use is at least 60 tpy, Group 1 room air emissions at area 
source facilities where EtO use is at least 40 tpy, and Group 2 room 
air emissions at area source facilities where EtO use is at least 4 
tpy.
---------------------------------------------------------------------------

    Pursuant to CAA section 112(d)(2)-(3) or 112(d)(5), we are 
establishing in this final rule the following emission standards for 
the previously unregulated sources:
     99 percent reduction for new and existing SCVs at 
facilities where EtO use is less than 1 tpy,
     99 percent reduction for new and existing ARVs facilities 
where EtO use is at least 1 tpy less than 10 tpy,
     99 percent reduction for new and existing ARVs at 
facilities where EtO use is less than 1 tpy,
     99.94 percent reduction for new and existing CEVs at major 
source facilities,
     99 percent emission reduction for new and existing CEVs at 
area source facilities,
     97 percent reduction for new and existing Group 1 room air 
emissions at major source facilities,
     80 percent emission reduction for new and existing Group 1 
room air emissions at area source facilities,
     86 percent reduction for new and existing Group 2 room air 
emissions at major source facilities, and
     80 percent emission reduction for new Group 2 room air 
emissions at area source facilities.
    As discussed in more detail below in section IV.C.3 of this notice, 
we are not finalizing any of the alternative emission limits for 
percent reduction standards on which we had solicited comment as part 
of the proposed rulemaking. Further, based on comments received on the 
proposed rulemaking, we are finalizing a revised best management 
practice (BMP) as the GACT standard under CAA section 112(d)(5) for 
existing Group 2 room air emissions at area sources. The BMP requires 
the in-chamber EtO concentration to be lowered to 1 part per million 
(ppm) before the chamber can be opened, as opposed to the proposed 
measure that would have required these 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. In addition, we are finalizing, as proposed, a 
requirement that facilities operate all areas with room air emissions 
subject to an emission standard in accordance with the PTE requirements 
of EPA

[[Page 24100]]

Method 204, irrespective of which CAA section 112 authority is invoked. 
Lastly, we are finalizing the removal of the 1 ppm alternative for ARVs 
at facilities where EtO use is at least 10 tpy. Section IV.B of this 
preamble provides in more detail the standards we are finalizing 
pursuant to CAA section 112(d)(2), 112(d)(3), and 112(d)(5), our 
rationales for the final standards and for changes since proposal, and 
a summary of key comments we received on the proposed standards and our 
responses.

C. What are the final rule amendments based on the risk review for the 
Commercial Sterilization Facilities source category?

    This section introduces the final amendments to the Commercial 
Sterilization Facilities NESHAP being promulgated pursuant to CAA 
section 112(f). As in the proposal, we determined that the risks for 
this source category were unacceptable under the previous provisions, 
and we are making a final determination of unacceptability as part of 
this final action, warranting necessary emission reductions as directed 
under the provisions we are finalizing pursuant to CAA sections 
112(d)(2), 112(d)(3), and 112(d)(5) in this rulemaking. When risks are 
unacceptable after considering the emission reductions from the 
standards in subpart O, we must determine the emissions standards 
necessary to reduce risk to an acceptable level. As such, we are 
promulgating final amendments to the Commercial Sterilization 
Facilities NESHAP pursuant to CAA section 112(f)(2) that will reduce 
risk to an acceptable level and will also provide an ample margin of 
safety to protect public health (see section IV.C of the preamble for 
further discussion). Based on comments received during the proposed 
rulemaking, we are finalizing the following EtO emissions standards 
under CAA section 112(f)(2):
     99.99 percent reduction for SCVs at facilities where EtO 
use is at least 30 tpy,
     99.9 percent reduction for SCVs at facilities where EtO 
use is at least 10 tpy but less than 30 tpy,
     99.8 percent reduction for SCVs at facilities where EtO 
use is at least 1 tpy but less than 10 tpy,
     99.9 percent reduction for ARVs at facilities where EtO 
use is at least 30 tpy,
     99.9 percent reduction for CEVs at area source facilities 
where EtO use is at least 60 tpy,
     98 percent reduction for Group 1 room air emissions at 
area sources facilities where EtO use is at least 40 tpy,
     98 percent reduction for Group 2 room air emissions at 
area sources facilities where EtO use is at least 20 tpy, and
     80 percent reduction for Group 2 room air emissions at 
area source facilities where EtO use is at least 4 tpy but less than 20 
tpy.
    We are not finalizing alternative emission limits for percent 
reduction standards for the same reasons discussed in section III.B of 
this preamble. Further, based on comments received during the proposed 
rulemaking, we are not finalizing any of the work practice standards 
that were proposed for facilities where the MIR remained greater than 
100-in-1 million after the imposition of requirements under ``Control 
Option 1''.\17\ These standards would have required facilities to limit 
their Group 2 room air emissions to a maximum volumetric flow rate of 
2,900 dry standard cubic feet per minute (dscfm) and a maximum EtO 
concentration of 30 parts-per-billion by volume (ppbv).
---------------------------------------------------------------------------

    \17\ Refer to section III.D.1.b of the proposal preamble (88 FR 
22790, April 13, 2023) for further discussion of Control Option 1.
---------------------------------------------------------------------------

    Section IV.C.3 of this preamble provides a summary of key comments 
we received regarding the risk review and our responses.

D. What are the final rule amendments based on the technology review 
for the Commercial Sterilization Facilities source category?

    We determined that there are developments in practices, processes, 
and control technologies that warrant revisions to the previous 
standards for this source category. Therefore, to satisfy the 
requirements of CAA section 112(d)(6), we are revising the standards to 
include, as in the proposed rule:
     99.8 percent reduction for SCVs at facilities where EtO 
use is at least 1 tpy but less than 10 tpy,
     99.6 percent reduction for existing ARVs at facilities 
where EtO use is at least 10 tpy, and
     99.9 percent reduction for new ARVs at facilities where 
EtO use is at least 10 tpy.
    Based on comments received during the proposed rulemaking, we are 
finalizing a 99.9 percent emission reduction standard for SCVs at 
facilities where EtO use is at least 10 tpy, which is different from 
the 99.94 percent emission reduction standard that was proposed (see 
section IV.D.3.a of this document for further discussion). We are not 
finalizing any of the alternative emission limits for percent reduction 
standards that we had solicited comment on as part of the proposed 
rulemaking. As part of the technology review, we also identified 
regulatory gaps (previously unregulated processes or pollutants) and 
are establishing new standards to fill those gaps as described in 
section III.B of this preamble. Section IV.D.3 of this preamble 
provides a summary of key comments we received regarding the technology 
review and our responses.

E. What are the final rule amendments addressing emissions during 
periods of startup, shutdown, and malfunction?

    In its 2008 decision in Sierra Club v. EPA, 551 F.3d 1019 (D.C. 
Cir. 2008), the United States Court of Appeals for the District of 
Columbia Circuit vacated portions of two provisions in our CAA section 
112 regulations governing the emissions of HAP during periods of SSM. 
Specifically, the court vacated the SSM exemption contained in 40 CFR 
63.6(f)(1) and 40 CFR 63.6(h)(1), holding that under section 302(k) of 
the CAA, emissions standards or limitations must be continuous in 
nature and that the SSM exemption violates the CAA's requirement that 
some section 112 standards apply continuously. We have eliminated the 
SSM exemption in this rule. Consistent with Sierra Club v. EPA, the EPA 
has established standards in this rule that apply at all times. We have 
also revised table 6 in subpart O (the General Provisions Applicability 
Table) in several respects as is explained in section III.G.1 of the 
proposal preamble (88 FR 22790). For example, we have eliminated and 
revised certain recordkeeping that is related to the SSM exemption as 
described in detail in the proposed rule and summarized again in 
section IV.E.1 of this preamble.
    In establishing standards in this rule, we have considered startup 
and shutdown periods and, for the reasons explained in section III.G.1 
of the proposal preamble and section IV.E of this preamble, have not 
established alternate standards for those periods.
    The EPA is also finalizing provisions related to malfunctions as 
proposed. Periods of startup, normal operations, and shutdown are all 
predictable and routine aspects of a source's operations. Malfunctions, 
in contrast, are neither predictable nor routine. Instead, they are, by 
definition, sudden, infrequent, and not reasonably preventable failures 
of emissions control, process, or monitoring equipment. (40 CFR 63.2) 
(Definition of malfunction). The EPA interprets CAA section 112 as not 
requiring emissions that occur during periods of malfunction to be 
factored into development of CAA section 112

[[Page 24101]]

standards. This reading has been upheld as reasonable by the D.C. 
Circuit in U.S. Sugar Corp. v. EPA, 830 F.3d 579, 606-610 (2016).
    Section IV.E.3 of this preamble provides a summary of key comments 
we received on the SSM provisions and our responses.

F. What other changes have been made to the NESHAP?

    This rule also finalizes, as proposed, revisions to several other 
requirements in the Commercial Sterilization Facilities NESHAP. We 
describe these revisions in this section as well as other proposed 
provisions that have changed since proposal.
1. Demonstrating Compliance
    In the majority of instances, parametric monitoring is used to good 
effect as an ongoing means of ensuring that these devices continue to 
get necessary emission reductions.\18\ However, given the nature of 
EtO, in which small amounts can have large risk impacts, parametric 
monitoring alone will not be sensitive enough to detect very small 
fluctuations in EtO concentration. Based on comments received during 
the proposed rulemaking, the EPA is finalizing a requirement to use EtO 
CEMS for demonstrating compliance. However, facilities where EtO use is 
less than 100 lb/year will have the option to use EtO CEMS or 
performance testing and parametric monitoring to demonstrate 
compliance. Based on comments received during the proposed rulemaking, 
we are promulgating the following requirements:
---------------------------------------------------------------------------

    \18\ Parametric monitoring is an approach that measures one or 
more key indicators of process operation or emission control device 
operation, typically on a continuous basis. The parameters are known 
to affect emission levels associated with the process or the control 
efficiency of the source's air pollution control device.
---------------------------------------------------------------------------

     Quarterly reporting of EtO CEMS data,
     Minimum data availability of 90 percent for EtO CEMS, and
     Use of either outlet volumetric flow rate monitors or 
differential pressure monitors to demonstrate continuous compliance 
with EPA Method 204.
    Based on comments received during the proposed rulemaking, we are 
not finalizing a requirement for the mass of EtO being routed to a 
control device from an SCV to be determined through inlet testing. 
Based on comments received during the proposed rulemaking, we are 
finalizing revisions to parametric monitoring requirements, and we are 
finalizing technical edits to Performance Specification 19 and QA 
Procedure 7.
2. Electronic Reporting
    To increase the ease and efficiency of data submittal and data 
accessibility, we are finalizing, as proposed, a requirement that 
owners or operators of commercial sterilization facilities submit 
compliance reports (being finalized at 40 CFR 63.366(b) and (c)), 
performance test reports (being finalized at 40 CFR 63.366(f)), and 
performance evaluation reports (being finalized at 40 CFR 63.366(g)) 
electronically through the EPA's Central Data Exchange (CDX) using the 
Compliance and Emissions Data Reporting Interface (CEDRI). The final 
rule requires that performance test results collected using test 
methods that are supported by the EPA's Electronic Reporting Tool (ERT) 
as listed on the ERT website \19\ at the time of the test be submitted 
in the format generated through the use of the ERT and that other 
performance test results be submitted in portable document format (PDF) 
using the attachment module of the ERT. Similarly, performance 
evaluation results of CEMS measuring relative accuracy test audit 
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 and 
other performance evaluation results be submitted in PDF using the 
attachment module of the ERT. For compliance reports, the final rule 
requires that owners or operators use the appropriate spreadsheet 
template to submit information to CEDRI. The final version of the 
template for these reports is in the docket and will be located on the 
CEDRI website.\20\ Furthermore, we are finalizing as proposed 
provisions that allow facility operators the ability to seek extensions 
for submitting electronic reports for circumstances beyond the control 
of the facility, i.e., for a possible outage in the CDX or CEDRI or for 
a force majeure event in the time just prior to a report's due date, as 
well as the process to seek such an extension.
---------------------------------------------------------------------------

    \19\ https://www.epa.gov/electronic-reporting-air-emissions/electronic-reporting-tool-ert.
    \20\ https://www.epa.gov/electronic-reporting-air-emissions/cedri.
---------------------------------------------------------------------------

    For a more detailed discussion of these final amendments to the 
Commercial Sterilization Facilities NESHAP, see section IV.G.2.g of the 
proposal preamble (88 FR 22790, April 13, 2023), as well as section 
VI.B below on compliance with the Paperwork Reduction Act. For a more 
thorough discussion 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, which is available in the docket for this rulemaking 
(see Docket Item No. EPA-HQ-OAR-2019-0178-0398).
3. Title V Permitting
    Because of the lack of other Federal requirements under the CAA 
that commercial sterilization facilities are subject to, as well as the 
robust monitoring and reporting requirements of the final rule, we are 
not finalizing a requirement for area source facilities subject to 
subpart O to obtain a title V permit from the delegated authority in 
which the source is located.
4. Combined Emission Streams
    To increase the ease and efficiency of complying with the revised 
NESHAP, we are finalizing, based on comments received during the 
proposed rulemaking, alternative compliance approaches for combined 
emission streams. For these streams, facilities will now be allowed to 
demonstrate compliance with a mass emission limit that is determined 
based on the emission standards to which the component streams are 
subject, as well as characteristics specific to those facilities. In 
addition, we are finalizing an option for owners and operators to 
demonstrate compliance with a site-wide emission limitation, as opposed 
to demonstrating compliance for each individual and combined emission 
stream.
5. Minor Clarifications and Corrections
    We are including several additional minor clarifying edits in the 
final rule based on comments received during the public comment period. 
The comments and our specific responses to these items can be found in 
the document, Summary of Public Comments and Responses for the 2024 
Risk and Technology Review for Commercial Sterilization Facilities, 
available in the docket for this rulemaking.

G. What are the effective and compliance dates of the standards?

    The revisions to the standards being promulgated in this action are 
effective on April 5, 2024. The compliance date for the standards 
promulgated pursuant to CAA section 112(f)(2) for the following 
existing sources is April 6, 2026:
     SCVs at facilities where EtO use is at least 1 tpy,
     ARVs at facilities where EtO use is at least 30 tpy,

[[Page 24102]]

     CEVs at area source facilities where EtO use is at least 
60 tpy,
     Group 1 room air emissions at area source facilities where 
EtO use is at least 40 tpy, and
     Group 2 room air emissions at area source facilities where 
EtO use is at least 4 tpy.
    The compliance date for the standards promulgated pursuant to CAA 
section 112(d)(2)-(3), 112(d)(5) or 112(d)(6) for the following 
existing sources is April 5, 2027:
     SCVs at facilities where EtO use is less than 1 tpy,
     ARVs at facilities where EtO use is less than 30 tpy,
     CEVs at major source facilities,
     CEVs at area source facilities where EtO use is less than 
60 tpy,
     Room air emissions at major source facilities,
     Group 1 room air emissions at area source facilities where 
EtO use is less than 40 tpy, and
     Group 2 room air emissions at area source facilities where 
EtO use is less than 4 tpy.
    As required by CAA section 112(i)(1), new sources must comply with 
each applicable standard immediately upon its effective date, which is 
April 5, 2024, or upon startup, whichever is later.
    The compliance schedules for existing sources have changed since 
proposal. We had proposed an 18-months compliance deadline for all of 
the proposed standards for existing sources. Based on the comments 
received, we have determined that 18 months is not a sufficient period 
for sources to comply with the CAA section 112(d)(2)-(3), 112(d)(5) and 
112(d)(6) standards for existing sources, for the following reasons:
     Most commercial sterilization facilities were not 
initially designed to be compliant with the PTE requirements of EPA 
Method 204. We have learned from the comments received that for these 
facilities, the capture requirements associated with the emission 
reduction standards for Group 1 and Group 2 room air emissions in the 
final rule will likely require a redesign of a portion if not all of 
the facility. Many facilities will also need to purchase additional 
equipment (e.g., fans, transformers, variable frequency drives, etc.) 
to meet the capture requirements. Moreover, compliance with the final 
emission standards will likely require the installation of additional 
control devices. We have reviewed the time that it has taken for 
previous projects of this nature to be completed, from submission of 
the initial State or local permit application to installation of the 
continuous compliance mechanisms. Based on this analysis, we find that 
the process of bringing a facility into compliance with the PTE 
requirements of EPA Method 204, as well as installing and verifying 
additional emission controls, can take approximately a year from permit 
submission to project completion. However, this estimate does not 
account for the time needed to design and plan before the initial 
permit application is submitted, nor for the time needed to avoid 
impacts on medical device supply chains, to procure control devices 
from a limited number of vendors, and to account for the other 
complexities identified below.
     The process of redesigning a facility or installing 
additional controls will require some reduction in sterilization 
capacity. Moreover, the process of coming into compliance with the 
standards may require multiple facilities to reduce their sterilization 
capacity simultaneously. Based on comments received during the proposed 
rulemaking, the average reduction in capacity during the re-design and 
installation period can range from 10 percent \21\ to 20 percent.\22\ 
In addition, there is already strain on the medical device supply 
chain, and it is difficult for most facilities to absorb any additional 
demand for sterilized product. Three years is needed to ensure that 
owners and operators can come into compliance with the emissions 
standards while at the same time minimizing any potential impacts to 
the medical device supply chain, for which reliability is important to 
protect public health.
---------------------------------------------------------------------------

    \21\ Commenter provided the following statement: ``For example, 
a 10% reduction in capacity across the 83 commercial sterilizers in 
the U.S. implies that an additional 8 sterilization facilities will 
be required to maintain existing throughput'' (see Docket Item No. 
EPA-HQ-OAR-2019-0178-0618).
    \22\ Commenter provided the following statement: ``During . . . 
upgrades, EtO sterilization capacity was reduced by more than 20 
percent as emissions control equipment was installed and tested.'' 
(see Docket Item No. EPA-HQ-OAR-2019-0178-0566).
---------------------------------------------------------------------------

     There are a limited number of vendors that specialize in 
the redesign of facilities to be compliant with the PTE requirements of 
EPA Method 204. In addition, there are a limited number of control 
technology vendors that supply the types of advanced control systems 
that the EPA expects will be necessary for facilities to comply with 
the final standards. Three years is needed to ensure that all owners 
and operators can receive the necessary services and have the proper 
equipment in place by the compliance date.
    For the same reasons explained above, existing sources will need 
more than the proposed 18 months to comply with the standards 
promulgated under CAA section 112(f)(2). As with standards promulgated 
under section 112(d)(2)-(3), 112(d)(5) and 112(d)(6), in most instances 
compliance with the section 112(f)(2) standards will require sources to 
plan, purchase, and install equipment for EtO control. For example, for 
SCVs at facilities where EtO use is at least 30 tpy, if an existing 
affected source currently does not achieve 99.99 percent control of EtO 
emissions and a new control system is needed to meet that limit, the 
facility will need time to properly engineer the project, obtain 
capital authorization and funding, procure the equipment, construct the 
equipment, start up the equipment, set up new software, develop 
operating procedures, and train operators on the new equipment. The 
additional factors identified above, such as avoiding impacts to 
medical device supply chains and securing control devices from a 
limited number of vendors, apply similarly to section 112(f)(2) 
standards as to standards promulgated under section 112(d)(2)-(3), 
112(d)(5) and 112(d)(6).
    If facilities commence work on these emissions reduction efforts 
immediately after this rule becomes effective, we believe that sources 
will be able to comply with the standards in this final rule within the 
two year compliance window set by Sec.  112(f)(4), without substantial 
interruption in operations.
    Specifically, we offer the following timeline as a general guide to 
completing the necessary upgrades in a timely manner:
     Step 1: Secure vendors for facility retrofits, control 
devices, EtO CEMS, and any other equipment and services that will be 
needed in order to comply with the NESHAP.
     Step 2: Work with vendors on (1) any new facility designs 
that will be required in order to meet the PTE requirements of EPA 
Method 204, (2) any new control system designs that will be required in 
order to meet the emission standards, (3) a schedule to ensure timely 
compliance with the NESHAP, and (4) purchase of the equipment that will 
be required in order to meet items (1) and (2), along with EtO CEMS.
     Step 3: Submit a permit application to the relevant 
permitting authority.
     Step 4: Complete the necessary facility retrofits, control 
device installations, and EtO CEMS installations.
     Step 5: Test the control systems and facility air handling 
systems in order to ensure that the NESHAP is being met.
    We recognize that this is a significant undertaking for the 
industry, and we encourage facilities to engage in these

[[Page 24103]]

steps as early as practicable, as opposed to delaying action until 
closer to the end of the compliance period.
    Although we believe sources that follow this timeline will be able 
to comply with these standards within two years, to minimize any 
potential impact to the medical device supply chain, we are allowing up 
to three years for existing sources to comply with section 112(d)(2)-
(3), 112(d)(5) and 112(d)(6) standards, the maximum timeframe 
authorized under CAA section 112(i)(3)(A). Further, CAA section 
112(i)(3)(B) and EPA's regulation at 40 CFR 63.6(i)(4)(i)(A) authorize 
States with delegated authority to implement and enforce this NESHAP to 
grant an existing source an additional year to comply with section 
112(d) standards, if such additional period is necessary for the 
installation of controls.\23\ In addition, for each standard, owners 
and operators will have 180 days after the end of the relevant 
compliance period to begin demonstrating compliance with that standard. 
See 40 CFR 63.7(a)(2).
---------------------------------------------------------------------------

    \23\ This flexibility has been available since the NESHAP was 
first promulgated (59 FR 62585, December 6, 1994) and continues to 
be available in the current NESHAP.
---------------------------------------------------------------------------

    Lastly, if more time is needed to comply with any standard in this 
final rule, CAA section 112(i)(4) provides that ``The President may 
exempt any stationary source from compliance with any standard or 
limitation under this section for a period of not more than 2 years if 
the President determines that the technology to implement such standard 
is not available and that it is in the national security interests of 
the United States to do so. An exemption under this paragraph may be 
extended for 1 or more additional periods, each period not to exceed 2 
years. The President shall report to Congress with respect to each 
exemption (or extension thereof) made under this paragraph.''

IV. What is the rationale for our final decisions and amendments for 
the Commercial Sterilization Facilities source category?

    For each issue, this section provides a description of what we 
proposed and what we are finalizing for the issue, the EPA's rationale 
for the final decisions and amendments, and a summary of key comments 
and responses. For all comments not discussed in this preamble, comment 
summaries and the EPA's responses can be found in the comment summary 
and response document available in the docket.

A. Amendments Addressing the Affected Source Definitions

1. What amendments did we propose to address the affected source 
definitions?
    For SCVs, ARVs, and CEVs, we proposed to define the affected source 
as the individual vent. For Group 1 and Group 2 room air emissions we 
proposed to define the affected source as the collection of all room 
air emissions for each group at any sterilization facility. More 
information concerning the affected source definitions is in section 
III.A. of the proposal preamble (88 FR 22790, April 13, 2023).
2. How did the affected source definitions change since proposal?
    We are finalizing the affected source definitions as proposed (88 
FR 22790, April 13, 2023).
3. What key comments did we receive on the affected source definitions 
and what are our responses?
    Comment: Two commenters suggested that the definition of an 
affected source should be based on control system outlets, stating that 
when emission streams are combined, the limit must be based on the 
actual achievable rate of control with further consideration for the 
modeled risk of the facility. One commenter suggested that the affected 
source should be defined as the sterilization facility as a whole, and 
another commenter stated the affected source definition(s) should 
consider destruction efficiency. Additionally, commenters expressed 
concerns that the affected source definitions for point sources (i.e., 
SCVs, ARVs, and CEVs) would disproportionately favor facilities with 
smaller capacity and facilities with multiple individual vents 
regardless of size. Specifically, one commenter stated that a facility 
with multiple individual vents would have a higher ``emission rate 
ceiling'' with respect to mass rate (i.e., lb/h) emission limits.
    Response: We disagree with the commenters' suggestion that the 
definition of an affected source should be based on control system 
outlets or the sterilization facility as a whole. There are many 
different ways in which emission sources can be combined and controlled 
at commercial sterilization facilities. If affected source definitions 
were based on control system outlets, it is not clear which outlets 
(and, by extension, emission source combinations) would be selected and 
what the criteria for selecting those outlets would be. It is not 
feasible to set an emission standard for every conceivable combination 
of emission sources. Furthermore, the commenters do not provide any 
suggestions on which control system outlets should be considered when 
defining affected sources. The most straightforward approach is to 
define the affected source as the emission source itself and to have 
owners and operators decide how best to combine and control emissions 
from affected sources at their facilities. With respect to defining the 
affected source as the sterilization facility as a whole, there is very 
limited data available where a performance test has been conducted for 
an entire facility. Furthermore, defining the affected source as the 
sterilization facility would require a compliance mechanism that some 
facilities may find unnecessarily complicated, given that compliance 
demonstration has typically been conducted on a source-by-source basis. 
It is not clear and the commenter does not provide any explanation on 
how to base an affected source definition on destruction efficiency.
    Lastly, regarding the comment that the definition of affected 
sources for point sources is disproportionally favorable to facilities 
with smaller capacity or with multiple individual vents, this is not an 
issue in the final rule. All of the emission standards in this final 
rule are in a percent reduction format, which is the same regardless of 
facility size or how many vents are in place. Therefore, concerns 
regarding ``emission rate ceilings'' are no longer relevant.
    Comment: One commenter stated that there is unnecessary complexity 
to the proposed definitions of Group 1 and Group 2 room air emissions 
due to the variability in size and facility configuration, particularly 
as they apply to the proposed format of the emission standards for 
these sources (i.e., lb/h). The commenter also stated that the 
definitions favor facilities which have smaller capacity and noted that 
individual facility characteristics must be considered for Group 1 and 
Group 2 emissions. Specifically, the commenter stated that emission 
rates should be based on technological feasibility to control 
emissions, including feasibility limitations regarding low inlet 
concentrations.
    Response: We disagree with one commenter's assertion that there is 
unnecessary complexity to the proposed definitions of Group 1 and Group 
2 room air emissions due to the variability in size and facility 
configuration. All sterilization facilities, regardless of size or 
configuration, follow the same basic procedure: sterilization and its 
associated activities (e.g., EtO storage and dispensing, vacuum pump

[[Page 24104]]

operation, handling of pre-aeration sterilized product), aeration, and 
shipping. Group 1 room air emissions simply cover all activities that 
occur prior to aeration, and Group 2 room air emissions cover all 
activities that occur after aeration. Combining room air emissions 
based on whether they occur before or after aeration is a clear way to 
defining room air emissions affected sources. It also reflects the most 
common controlled room air configuration that we have observed. With 
respect to considering individual facility characteristics The simplest 
breakdown of controlled room air emissions that we have observed 
involves capturing and routing all emissions from post-aeration 
handling of sterilization material to one control system, and then 
capturing and routing all other room air emission sources (i.e., Group 
1 room air emissions) to another control system. It is important to 
define the affected sources for room air emissions in this manner so 
that owners and operators can have flexibility in how they chose to 
control their emissions,\24\ and so that facilities who have already 
chosen to control their emissions in this manner can continue to do so 
while minimizing any potential compliance issues. With respect to the 
comment that the definition of affected sources for room air emissions 
is disproportionally favorable to facilities with smaller capacity, the 
comment appears to pertain more to the setting of the emission 
standards themselves, rather than the affected source definition. As 
discussed in section IV.B.3.b of this preamble, we are no longer 
finalizing mass rate emission standards, and we are accounting for 
technical feasibility (e.g., manufacturer guarantees, emission 
reductions achieved in performance tests) when finalizing emission 
standards. The emission standards in this final rule for room air 
emissions are in a percent reduction format, which is the same 
regardless of facility size.
---------------------------------------------------------------------------

    \24\ The EPA has not observed any instance where a facility is 
routing a portion of its Group 1 room air emissions to one control 
system, and the other portion to a different control system.
---------------------------------------------------------------------------

4. What is the rationale for our final approach and final decisions to 
address the affected source definitions?
    We evaluated the comments on our proposed affected source 
definitions. For the reasons explained in the proposed rule (88 FR 
22790, April 13, 2023), we determined that these amendments are 
necessary because the definition of an ``affected source'' at 40 CFR 
63.2 is not appropriate for this source category. More information 
concerning the amendments we are finalizing for affected source 
definitions is in the preamble to the proposed rule and in the comments 
and our specific responses to the comments in the document, Summary of 
Public Comments and Responses for the Risk and Technology Review for 
Commercial Sterilization Facilities, available in the docket for this 
rulemaking. Therefore, we are finalizing the affected source 
definitions as proposed.

B. Amendments Pursuant to CAA Sections 112(d)(2), 112(d)(3), and 
112(d)(5) for the Commercial Sterilization Facilities Source Category

1. What did we propose pursuant to CAA sections 112(d)(2), 112(d)(3), 
and 112(d)(5) for the Commercial Sterilization Facilities source 
category?
    We proposed to establish standards under CAA sections 112(d)(2)-(3) 
and 112(d)(5) for the following emission sources that were unregulated: 
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. We also proposed a technical correction to the 
emission standard for ARVs at facilities where EtO use is at least 10 
tpy. We proposed the following emission standards pursuant to CAA 
section 112(d)(2)-(3):
     3.2E-4 lb/h for new and existing CEVs at facilities where 
EtO use is at least 10 tpy,
     1.3E-3 lb/h for new and existing Group 1 room air 
emissions at major source facilities, and
     2.8E-3 lb/h for new and existing Group 2 room air 
emissions at major source facilities.
    For more information, see section III.B of the proposal preamble 
(88 FR 22790, April 13, 2023). We proposed the following emission 
standards pursuant to CAA section 112(d)(5):
     99 percent emission reduction for new and existing SCVs at 
facilities where EtO use is less than 1 tpy,
     99 percent emission reduction for new and existing ARVs at 
facilities where EtO use is at least 1 tpy but less than 10 tpy,
     99 percent emission reduction for new and existing ARVs at 
facilities where EtO use is less than 1 tpy,
     99 percent emission reduction for new and existing CEVs at 
facilities where EtO use is at least 1 tpy but less than 10 tpy,
     99 percent emission reduction for new and existing CEVs at 
facilities where EtO use less than 1 tpy.
     1.3E-3 lb/h emission limit for new and existing Group 1 
room air emissions at area source facilities, and
     2.8E-3 lb/h emission limit for new Group 2 room air 
emissions at area source facilities.
    These are emissions standards that reflect the use of generally 
available control technologies. For more information, see section III.B 
of the proposal preamble (88 FR 22790, April 13, 2023).
    For existing Group 2 room air emissions at area source facilities, 
pursuant to CAA section 112(d)(5), we proposed a requirement for 
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. This is a BMP 
that would reduce EtO use per sterilization cycle (i.e., pollution 
prevention). For more information, see section III.B.8.g of the 
proposal preamble (88 FR 22790, April 13, 2023). In order to ensure 
complete capture of EtO emissions and, in turn, compliance with the 
proposed standards, we proposed to require each facility to operate 
areas with room air emissions subject to an emission standard in 
accordance with the PTE requirements of EPA Method 204 of appendix M to 
40 CFR part 51. For more information, see section III.B of the proposal 
preamble (88 FR 22790, April 13, 2023).
    We addressed a necessary correction to the emission standards for 
these sources in 40 CFR 63.362(d) that allow 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.'' We proposed removing 
the less stringent 1 ppmv concentration alternative for these sources 
because it is not equivalent and therefore not an appropriate 
alternative to 99 percent emission reduction standard. For more 
information, see section III.B.2 of the proposal preamble (88 FR 22790, 
April 13, 2023).
2. How did the revisions pursuant to CAA sections 112(d)(2), 112(d)(3), 
and 112(d)(5) change since proposal for the Commercial Sterilization 
Facilities source category?
    We are finalizing as proposed the following standards under CAA 
section 112(d)(5):
     99 percent emission reduction for new and existing SCVs at 
facilities where EtO use is less than 1 tpy,
     99 percent emission reduction for new and existing ARVs at 
facilities

[[Page 24105]]

where EtO use is at least 1 tpy but less than 10 tpy, and
     99 percent emission reduction for new and existing ARVs at 
facilities where EtO use is less than 1 tpy.
    In addition, we are finalizing a requirement for each facility to 
operate areas with room air emissions subject to an emission standard 
in accordance with the PTE requirements of EPA Method 204 of appendix M 
to 40 CFR part 51. We are also finalizing the removal of the 1 ppm 
alternative for ARVs at facilities where EtO use is at least 10 tpy, as 
proposed.
    Based on comments received during the proposed rulemaking, we have 
revised the proposed standards for the following affected sources. The 
final emission standards pursuant to CAA sections 112(d)(2), 112(d)(3), 
and 112(d)(5) are as follows:
     99.94 percent emission reduction for new and existing CEVs 
at major source facilities,
     99 percent emission reduction for new and existing CEVs at 
area source facilities,
     97 percent emission reduction for new and existing Group 1 
room air emissions at major source facilities,
     80 percent emission reduction for new and existing Group 1 
room air emissions at area source facilities,
     86 percent emission reduction for new and existing Group 2 
room air emissions at major source facilities,
     For existing Group 2 room air emissions at area source 
facilities, lower the EtO concentration within each sterilization 
chamber to 1 ppm before the chamber can be opened, and
     80 percent emission reduction for new Group 2 room air 
emissions at area source facilities.
    For new and existing CEVs at major source facilities, as well as 
new and existing room air emissions at major source facilities, based 
on comments received during the proposed rulemaking, we have re-
calculated the MACT floor based on percent emission reduction, as 
opposed to mass rate emissions. The primary reason for finalizing this 
change is that there is a serious concern that mass rate emission 
standards could result in operational reductions that could adversely 
impact the medical supply chain. The revised MACT floor for new and 
existing CEVs at major source facilities is 99.94 percent emission 
reduction. Because we were unable to identify more stringent (i.e., 
beyond the floor or ``BTF'') options that are cost-effective, we are 
finalizing 99.94 percent emission reduction as the MACT standard under 
CAA section 112(d)(2)-(3) for new and existing CEVs at major source 
facilities. The revised MACT floor for new and existing Group 1 room 
air emissions at major source facilities is 90 percent emission 
reduction. We were able to identify a more stringent (i.e., 97 percent 
control) and cost-effective BTF option and, therefore, we are 
finalizing a 97 percent emission reduction standard as the MACT 
standard under CAA section 112(d)(2)-(3) for new and existing Group 1 
room air emissions at major source facilities. The revised MACT floor 
for new and existing Group 2 room air emissions at major source 
facilities is 86 percent emission reduction. Because the concentration 
that corresponds to this emission reduction is three times the 
representative detection level (RDL) for EtO, there are no BTF options 
to consider due to the potential difficulty of demonstrating compliance 
with limits lower than the MACT floor. Therefore, we are finalizing 86 
percent emission reduction as the MACT standards for new and existing 
Group 2 room air emissions at major source facilities. For more 
information, see section IV.B.3.b of this preamble.
    For both new and existing Group 1 room air emissions at area source 
facilities, as well as new Group 2 room air emissions at area source 
facilities, based on comments received during the proposed rulemaking, 
we are finalizing an 80 percent emission reduction standard, consistent 
with the manufacturer guarantee for the control technology on which the 
standard is based. The primary reason for the change from mass rate to 
percent reduction is that there is a serious concern that mass rate 
emission standards could result in operational reductions in order to 
meet the standards while still ensuring work health and safety, but 
that could adversely impact the medical supply chain. In addition, 
while some sources have demonstrated emission reductions higher than 80 
percent, those reductions are limited to facilities with higher EtO 
usage rates, and we cannot determine whether smaller users of EtO can 
meet those emission reductions. For more information, see section 
IV.B.3.b of this preamble.
    For existing Group 2 room air emissions at area source facilities, 
based on comments received during the proposed rulemaking, we are 
finalizing a revised BMP due to concerns that the BMP that we proposed 
(as well as alternatives for which we solicited comment in the 
proposal), would adversely impact the medical supply chain due to 
inefficiencies that would arise, as well as having to lengthen cycle 
dwell times in order to ensure sterility. The final requirement reduces 
existing Group 2 room air emissions at area source facilities by 20 
percent, does not interfere with sterility assurance, and is expected 
to impact only 20 percent of facilities. We do not anticipate any 
severe negative impacts to the medical supply chain as a result of 
finalizing this requirement. For more information, see section IV.B.3.a 
of this preamble.
3. What key comments did we receive on the proposal revisions pursuant 
to CAA section 112(d)(2), 112(d)(3), and 112(d)(5), and what are our 
responses?
    This section provides comment and responses for the key comments 
received regarding BMPs, mass rate emission standards, PTE, and 
warehouses. Other comment summaries and our responses for additional 
issues raised regarding these activities, as well as issues raised 
regarding our proposed emission standards for SCVs and ARVs at 
facilities where EtO use is less than 1 tpy, ARVs at facilities where 
EtO use is a least 1 tpy but less than 10 tpy, room air emissions at 
major source facilities, and our proposed technical correction to the 
emission standard for ARVs at facilities where EtO use is at least 10 
tpy can be found in the document, Summary of Public Comments and 
Responses for the Risk and Technology Review for Commercial 
Sterilization Facilities, available in the docket for this rulemaking.
a. BMP
    Comment: Several commenters contended that we should not 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. They stated 
that owners and operators should have the flexibility to optimize 
cycles using a variety of ISO/AAMI 11135 methods and that we should not 
limit or restrict the validation method that may be used.
    One commenter stated that requiring facilities to follow the Cycle 
Calculation or Bioburden/Biological Indicator Approach would result in 
more dedicated product loads, more cycles needed to sterilize different 
project mixes, and most chambers not being filled to capacity. The 
commenter stated that de-consolidation of existing cycles to implement 
an appropriate Cycle Calculation or Bioburden/Biological Indicator 
approach would require (1) creation and validation of new product 
families, new process challenge devices, and biological indicators, (2) 
cycle development, and (3) maintenance through requalification and 
annual reporting. The commenter noted that the

[[Page 24106]]

extra burden associated with maintaining more cycles would create more 
work and require more chamber time, resulting in less sterilization 
capacity. Two commenters stated that requiring either the Cycle 
Calculation or Bioburden/Biological Indicator approach could limit 
research for product innovation as available development time in EtO 
sterilization chambers would be taken up for optimizing existing 
products.
    Two commenters stated the ISO standards were intended for the 
process of EtO sterilization and not emission reduction or controls. 
One commenter further contended it is a faulty approach to base 
emission standards on international standards, as these standards are 
revised periodically and may continue to evolve. Another commenter 
noted that ISO/AAMI standards are currently being revised to be more 
flexible to achieve optimized cycles, while minimizing impact on 
sterilization capacity. The commenter contended that cycle validation 
must focus on achieving sterility required for patient safety and 
assuring product performance and reliability, and that reducing EtO use 
cannot take priority over patient safety.
    One commenter stated that conducting Cycle Calculation studies for 
every product type or category would not be feasible with the current 
capacity. The commenter stated this would require effort to redesign 
sterilization cycles, evaluate product and packaging performance, and 
validate the redesigned cycles. The commenter also stated that the new 
validation work will impact sterilization capacity as sterilizer 
equipment is not available for production use during study times (i.e., 
production capacity is diverted to cycle validation). The commenter 
further stated that sites that use more than one vendor would have to 
redesign sterilization cycles at each vendor and that, given the 
limited resources and expertise, this would not be possible to achieve 
on this scale. Another commenter stated they have not been able to 
ensure product sterility using Cycle Calculation approach.
    Finally, one commenter stated that the Bioburden/Biological 
Indicator methods limit the number of products that can be validated in 
a single cycle. The commenter stated that the Bioburden/Biological 
Indicator approach may be limited to a range of products with similar 
attributes and drive up the number of required cycles. The commenter 
also stated that each validated cycle will require requalification 
every few years, and the additional testing at sterilizers and testing 
laboratories will decrease available sterilization capacity. The 
commenter stated that the inability to fill a sterilization chamber 
fully with product and waiting until full can lead to inefficient use 
of sterilization chambers and supply issues. Another commenter stated 
the Bioburden/Biological Indicator approach results in additional cost 
and delays, as it requires that the product bioburden levels be 
enumerated and characterized, and that consistency in the bioburden 
population and the bioburden's resistance to the sterilization process 
remain relatively stable over a multi-year period. The commenter also 
stated that it may take many years to establish the range in numbers 
and types of bioburden to properly perform a validation using this 
proposed Bioburden/Biological Indicator approach. Another commenter 
stated that the Bioburden approach would require upgrades to supplier 
facilities, manufacturing facility, and microbiological control 
practices.
    Response: We agree with the commenters' concerns regarding 
potential inefficiencies in the sterilization process that may arise 
from 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, along with the potentially adverse impacts to the medical 
supply chain that could result from the proposed approach. These 
inefficiencies include reduced cycle optimization (i.e., not being able 
to sterilize as much product per load or chamber), having to run more 
cycles overall in order to meet the demand for sterile medical devices, 
and diverting already strained resources away from normal operations to 
developing new cycle validations. We also agree with the commenters' 
concerns that requiring facilities to follow this requirement would 
limit research for product innovation. Given the current strain on 
resources, some companies may not be able to invest in additional 
chambers to conduct research. In addition, we agree with the 
commenters' concerns that because this requirement is based on 
international standards, which are revised periodically, this could 
result in potential future complications. Therefore, we are not 
including this requirement in the final rule.
    Comment: As mentioned above, the EPA solicited comments on several 
other BMPs, including limiting EtO concentration limit and limiting 
packaging and pallet material. Two commenters stated that it is not 
technically feasible for facilities and products to meet a 290 
milligrams per liter (mg/L) EtO concentration limit. One commenter 
stated that many industry guidelines and studies show that 400 mg/L is 
the minimum recommended concentration, and many products use higher 
concentrations to meet sterility assurance and product quality 
requirements as set forth by FDA. Another commenter stated that process 
efficiency is reduced with concentrations below 400 mg/L and that 
efficiency is constant at concentrations greater than 500 mg/L. One 
commenter indicated that an EtO concentration range of 400 to 650 mg/L 
is common practice because it achieves microbiological lethality for 
most products within a reasonable exposure time. Another commenter 
stated that product design, stability post-sterilization, and lethality 
are the drivers behind the choice of EtO concentration. The commenter 
also stated that research and development with biological indicators is 
routinely conducted using 600 mg/L cycles and that enforcing a lower 
limit may have an unintended negative consequence on the availability 
of biological indicators required for sterilization process validation 
and routine monitoring. One commenter stated we should not propose to 
limit the EtO concentration to 290 mg/L for small facilities and that 
we should, instead, allow performance-based standards. In addition, 
several commenters stated that an upper-bound limit on EtO 
concentration may lead to longer cycle times and dwell times and that 
longer dwell times would impact sterilization capacity and would lead 
to offshoring, as well as the construction of additional facilities.
    One commenter stated limiting packaging and pallet material will 
interrupt trade, reduce innovation, increase the cost of medical 
devices, and disrupt the medical device manufacturing industry without 
a quantifiable reduction in EtO emissions. Two commenters stated that 
packaging and pallet material selection will drive the design of 
medical products. Two commenters noted that packaging requirements are 
in place to ensure a sterile barrier until use and to prevent product 
damage. One commenter stated packaging must pass rigorous test 
requirements, according to industry standards. Another commenter 
indicated that facilities use barcode instructions for use (IFUs) in 
place of paper IFUs when possible. However, paper IFUs are regulated by 
FDA. Two commenters noted that paper IFUs have not been documented to 
be a source of residual emissions. Another commenter

[[Page 24107]]

stated that there is no evidence that barcode materials would have less 
EtO retention than paper, and that labeling decisions have practical 
and legal considerations. One commenter noted that a minimal amount of 
plastic wrap is used to ensure the structural integrity of pallets 
during shipping and that excessive plastic is not in the interest of 
sterilization facilities, as it slows EtO penetration. The commenter 
also stated that kits are transported in cardboard to protect from 
punctures, and it is not possible to eliminate cardboard. A puncture to 
a kit means the kit needs to be re-sterilized, requiring use of 
additional EtO. One commenter stated that changes to pallet material 
could have supply chain issues given interoperability and weight 
requirements. Finally, another commenter stated that pallet materials 
impact the strength and design of pallet, and any issues would have 
implications for the entre medical device supply chain.
    Response: We agree with the commenters' concerns regarding the 
issues with prescribing an upper-bound limit on in-chamber EtO 
concentration, as well as the negative impacts to the medical supply 
chain that could result from increasing the dwell time to maintain 
sterility as an outcome of such a requirement. Therefore, we are not 
including this requirement in the final rule. We also agree with the 
commenters' concerns regarding the need to ensure a sterile barrier 
through sufficient packaging, as well as the potential supply chain 
impacts from placing limits on the types of pallets that may be used. 
Therefore, we are not requiring limits on packaging or transport 
materials as part of this rulemaking.
    Comment: One commenter recommended an end of sterilization cycle 
chamber limit of less than 1 ppm (with a zero mg/L reading) in the 
sterilization chamber (EtO remaining calculated measurement) as a BMP. 
The commenter stated that removing EtO from the sterilization chamber 
is the most efficient stage for EtO removal. The commenter further 
stated that longer EtO dwell times, as well as the potential for the 
elimination of nitrogen gas washes to keep total cycle time equivalent, 
could result in more EtO residual at aeration and the greater potential 
for room air emissions after aeration.
    Response: We agree with the commenter's suggestion of a requirement 
to limit the in-chamber EtO concentration to 1 ppm. It does not 
interfere with sterility assurance, and, based on responses to the 
December 2019 questionnaire and September 2021 Information Collection 
Request (ICR), 80 percent of all commercial sterilization facilities, 
regardless of annual EtO use, are already meeting this limit. Those who 
are not meeting the limit currently are close to the limit,\25\ so we 
do not anticipate any severe negative impacts to the medical device 
supply chain as a result of finalizing this requirement. We estimate 
that the emission reductions from applying this requirement to the 
source category would be 20 percent. In addition, since 80 percent of 
facilities are already meeting this limit, this would result in an 80 
percent reduction in costs. We have evaluated the changes in cost, 
emissions, and cost-effectiveness for this BMP, and it is more cost-
effective than the other options we considered. Therefore, for Group 2 
room air emissions we are finalizing the BMP such that the in-chamber 
EtO concentration is to be lowered to 1 ppm before the chamber can be 
opened. We note that, even though this BMP is expected to result in 
fewer emission reductions than the BMP we proposed, this rule will 
still reduce EtO emissions (and, therefore, lifetime cancer risks) in 
multiple communities across the country. As discussed in section 
IV.C.2.a.iii, this BMP will ultimately apply only to facilities where 
EtO use is less than 4 tpy. We are finalizing the requirement that area 
source facilities whose EtO usage is at least 4 tpy but less than 20 
tpy and area source facilities whose EtO usage is at least 20 tpy are 
required to reduce Group 2 room air emissions by 80 percent and 98 
percent, respectively (see section IV.C.2.a.iii for more information). 
For SCVs and ARVs at facilities where EtO use is less than 1 tpy, as 
well as ARVs at facilities where EtO use is less than 10 tpy, our 
general rationale for proposing emission standards over the BMP was 
that emission standards would both achieve greater emission reduction 
and incur fewer annual costs than the BMP. However, even considering 
lower annual costs for the BMP, the emission standards would still 
achieve greater emission reduction. Therefore, for SCVs and ARVs at 
facilities where EtO use is less than 1 tpy, as well as ARVs at 
facilities where EtO use is less than 10 tpy, we are finalizing the 
emission standards as proposed pursuant to CAA section 112(d)(5). For 
CEVs at area source facilities, as well as room air emissions at area 
source facilities, we are also evaluating percent emission reduction 
standards, as opposed to mass rate emission standards. The revised GACT 
analyses for those emission sources are presented in section IV.B.3.b 
of this preamble.
---------------------------------------------------------------------------

    \25\ The highest concentration that was reported prior to 
opening the chamber door was 20 ppm. While this may seem high, this 
is reduced from starting EtO concentrations of several thousand ppm 
(see section IV.F.3 of this preamble for further discussion).
---------------------------------------------------------------------------

    Comment: Several commenters stated that we do not have the 
legislative authority or expertise to regulate sterilization cycles and 
that FDA is the Federal agency that has authority to regulate medical 
device sterilization. They stated that Congress gave FDA the authority 
to ensure the availability of safe and effective medical products and 
that we must not finalize any regulatory requirements that are under 
FDA purview.
    Response: The EPA proposed the BMP (i.e., require facilities to 
follow either the Cycle Calculation Approach or the Bioburden/
Biological Indicator Approach) pursuant to CAA section 112(d)(5), which 
authorizes the EPA to set standards for area sources that provide for 
the use of generally available control technologies or management 
practices to reduce emissions. In addition, CAA section 112(h)(1) 
authorizes the EPA to promulgate a design, equipment, work practice or 
operational standard, or a combination thereof, if the EPA does not 
think it can prescribe an emission standard. We have identified 
modification of the post-sterilization process (e.g., reducing the EtO 
concentration within the sterilization chamber prior to opening the 
chamber) as a BMP that can reduce EtO emissions from certain affected 
sources at commercial sterilization area source facilities. Neither CAA 
section 112(d)(5) nor section 112(h)(1) limits the scope of management 
or work practices that the EPA may consider in setting standards to 
control HAP, nor did the commenter identify any such legal limitation 
in the CAA or other applicable legal authorities. As discussed above, 
we are not finalizing the proposed BMP; in response to comment, we are 
finalizing a requirement for area source facilities with existing Group 
2 room air emissions to lower the in-chamber EtO concentration to 1 ppm 
before the chamber is opened.\26\ As discussed in

[[Page 24108]]

section IV.C.2.a.iii of this preamble, this requirement will ultimately 
apply only to existing Group 2 room air emissions at facilities where 
EtO use is less than 4 tpy. Based on responses to the December 2019 
questionnaire and the September 2021 ICR, we have not identified any 
facilities where EtO use is less than 4 tpy that are not currently 
meeting this requirement. Therefore, in general, we do not anticipate 
that any facilities will need to go through a new cycle validation as a 
result of this requirement. Based on our conversations with FDA, this 
requirement is not anticipated to have an adverse impact on the medical 
device supply chain.
---------------------------------------------------------------------------

    \26\ We have previously regulated the in-chamber EtO 
concentration when we established standards for CEVs at facilities 
where EtO use is at least 1 tpy but less than 10 tpy (59 FR 62586, 
December 6, 1994). These requirements were removed initially due to 
safety concerns regarding the regulation of emissions from CEVs, not 
related to any limitations on our authority. See discussion in 
section III.B.5 of the proposal preamble (88 FR 22790, April 13, 
2023) for more information regarding why safety is not a concern 
regarding the requirements finalized in this action.
---------------------------------------------------------------------------

b. Mass Rate Emission Standards
    Comment: Several commenters were opposed to mass rate emission 
standards, stating that they do not account for the substantial 
variability among volumetric flow rates in sterilization operations. 
The commenters expressed concerns with potential operational reductions 
needed in order to meet the standards while still ensuring worker 
health and safety, as well as compliance with EPA Method 204. The 
commenters suggested that we finalize emission reduction and outlet 
concentration standards instead. In addition, these commenters 
recommended that these standards be based on control device 
manufacturer guarantees. One commenter stated that, based on their 
discussions with control device manufacturers, they believe that the 
best and most advanced technologies will be guaranteed to meet a 99 
percent emission reduction standard for CEVs and an 80 percent emission 
reduction standard for room air emissions.
    Response: We agree with the commenters' concerns regarding the 
potential impacts of mass rate emission standards. Given the low outlet 
EtO concentration of these streams, along with current EtO detection 
levels, a mass rate emission standard essentially functions as an 
upper-bound limit on volumetric flow rate. It may not be appropriate to 
limit volumetric flow rate in this fashion, as additional flow may be 
needed in order to demonstrate compliance with EPA Method 204 or to 
ensure worker health and safety. If volumetric flow rate is limited, a 
facility may be forced to reduce its sterilization capacity in order to 
meet the mass rate emission standards. However, we disagree with the 
commenters' suggestion that outlet concentration standards be 
considered. We are concerned that some owners and operators may choose 
to dilute the air flow of the emissions stream rather than control 
emissions, in order to meet an outlet concentration standard, which 
would not result in emission reductions. In order to ensure emission 
reductions from an outlet concentration standard, an upper-bound limit 
on the volumetric flow rate would be necessary. As we have discussed 
before, this may be inappropriate for the source category. Therefore, 
although we proposed mass emission rate standards, we are finalizing 
percentage emission reduction standards in their place, and those 
specific standards are discussed later in this section.
    We re-calculated the MACT floor for existing CEVs at major source 
facilities. We ranked the percent reduction performance of the CEVs 
``for which the EPA has emissions information'' and found the best 
performing 12 percent of CEVs consists of one CEV that is being 
controlled by a gas/solid reactor.\27\ Because the variability and 
uncertainty associated using available, short-term data would tend to 
reduce the minimum percent reduction, we then used the lower, not 
upper, prediction limit approach to develop the MACT floor for existing 
sources.\28\ The LPL 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. For LPLs, our practice is to use the first percentile, or LPL 1, 
as that is the level of emission reductions 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 LPL 1 value of 
the existing source MACT floor is 99.94 percent emission reduction. The 
LPL 1 EtO concentration that corresponds to this emission reduction 
rate is 49 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 
makeup 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, 10 ppbv 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 (making them lower). In the meantime, consistent with 
our practice regarding reducing relative measurement imprecision by 
applying a multiplication factor of three to the 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,\29\ we apply a multiplication factor of three 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 percent 
emission reduction, inlet EtO concentration, and outlet EtO 
concentration:
---------------------------------------------------------------------------

    \27\ See CAA section 112(d)(3). See also, National Ass'n of 
Clean Water Agencies v. EPA, 734 F.3d 1115, 1131 (2013) (citing 
Sierra Club v. EPA, 167 F.3d 658, 661 and 662) (``We accorded 
Chevron deference to EPA's . . . estimate of the MACT floor, noting 
that the requirement that the existing unit floors `not be less 
stringent than the average emissions limitation achieved by the best 
performing 12 percent of units' does not, on its own, dictate `how 
the performance of the best units is to be calculated, . . . [and] 
recognizing that `EPA typically has wide latitude in determining the 
extent of data gathering necessary to solve a problem.' ''
    \28\ The variability for a DRE format limit requires use of a 
lower prediction limit (LPL), the UPL template was therefore 
modified for use to determine the LPL; rather than use of the 99th 
percentile that captures the ``right tail'' of the data 
distribution, the LPL template uses the 1st percentile, i.e., 
captures the ``left tail'' of the data distribution (the t-statistic 
is 0.01). The LPL differs from the more commonly used UPL in that 
variability and uncertainty associated with percent reduction limits 
tend to make the predicted limits smaller than their averages; for 
UPL applications, variability and uncertainty associated with 
emission limits tend to make those predicted limits larger than 
their averages. Both approaches--UPL and LPL--rely on the same set 
of equations developed for the UPL; they only differ in the selected 
percentile. In other words, the LPL relies on calculations 
associated with the first percentile (LPL 1) of the data 
distribution, which is below the fiftieth percentile (LPL 50), or 
average for data with a normal distribution, while the UPL relies on 
calculations associated with the ninety-ninth percentile (UPL 99) of 
the data distribution, which is above the fiftieth percentile (UPL 
50), or average for data with a normal distribution. Also note that 
for data in a normal distribution, LPL 50 = UPL 50.
    \29\ See the discussion in the MATS rule preamble at 77 FR 9370, 
February 16, 2012.
[GRAPHIC] [TIFF OMITTED] TR05AP24.000

    Where, ER is the percent emission reduction, EtOIM is 
the inlet EtO mass, and EtOOM is the outlet EtO mass. Since

[[Page 24109]]

the outlet EtO concentration that corresponds to the MACT floor of 
99.94 percent emission reduction is above 3xRDL, there are more 
stringent (i.e., BTF) options to consider.\30\ We considered two BTF 
options for reducing EtO emissions from this source: the first option 
is 99.95 percent emission reduction, and the second option reflects the 
most stringent emission reduction for which compliance can be 
demonstrated. With respect to the second option, the most stringent 
emission reduction for which compliance can be demonstrated is that 
which corresponds to an outlet concentration of 30 ppbv (i.e., 3xRDL). 
This emission reduction is 99.96 percent, which is lower than all of 
the reported emission reductions in the test runs that were used to 
calculate the MACT floor. The impacts of these options are presented in 
table 7. Because we have not identified any major source facilities 
with existing CEVs, the impacts are based on a model plant for existing 
CEVs at a synthetic area source facility with the following assumptions 
reflecting the average of each of the parameters at synthetic area 
source facilities:
---------------------------------------------------------------------------

    \30\ As Judge Williams explained in his concurring opinion in 
Sierra Club v. EPA, CAA ``Section 112(d)(2) calls for emissions 
standards that are the most stringent that the EPA finds to be 
`achievable,' taking into account a variety of factors including 
cost. . . . The ``achievable'' standards have come to be known as 
the ``beyond-the-floor'' standards, . . . meaning, obviously, ones 
more stringent than the ``floors'' established under Sec.  
112(d)(3).'' 479 F.3d 875, 884 (D.C. Cir. 2007).
---------------------------------------------------------------------------

     Annual EtO use: 200 tpy.
     Annual operating hours: 8,000.
     Portion of EtO going to CEVs: 1 percent.
     CEV flow rate: 278 cubic feet per second (cfs).

 Table 7--Nationwide Emissions Reduction and Cost Impacts of BTF Options Considered Under CAA Sections 112(d)(2) and 112(d)(3) for CEVs at Major Source
                                                                       Facilities
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                       Total capital   Total annual    EtO emission reductions   Cost effectiveness ($/
                Option                       Proposed standard        investment ($)   costs ($/yr)             (tpy)                   ton EtO)
--------------------------------------------------------------------------------------------------------------------------------------------------------
MACT Floor...........................  99.94 percent emission               $830,000        $176,000  2.4E-2 [480 lb/yr]......  $735,000 [$370/lb].
                                        reduction.
1....................................  99.95 percent emission                184,000          65,500  2.0E-4 [0.4 lb/year]....  328,000,000 [$164,000/
                                        reduction.                                                                               lb].
2....................................  99.96 percent emission                184,000          66,200  2.0E-4 [0.4 lb/year]....  331,000,000 [$166,000/
                                        reduction.                                                                               lb].
--------------------------------------------------------------------------------------------------------------------------------------------------------

    While we acknowledge that EtO is a highly toxic HAP, the cost 
estimates above are far outside the range of the cost-effectiveness 
values that we have determined to be cost-effective for highly toxic 
HAPs (e.g., 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). Based on the 
estimates above, we find neither option to be cost effective. 
Therefore, the final MACT standard for existing CEVs at major source 
facilities is 99.94 percent emission reduction.
    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 99.94 percent 
emission reduction. As explained above, because this emission reduction 
limit is above the lowest level at which compliance can be 
demonstrated, the EPA considered more stringent (i.e., BTF) options. We 
considered the same BTF options as those evaluated for existing CEVs at 
major source facilities, for the same reasons explained above. The 
first BTF option would require achieving 99.95 percent emission 
reduction, and the second BTF option would require achieving 99.96 
percent emission reduction. The impacts of these options are presented 
in table 7 of this preamble. Because we have not identified any major 
source facilities with existing CEVs, the impacts are based on a model 
plant for existing CEVs at a synthetic area source facility. Based on 
the estimates above and for the reason explained above, we find neither 
option to be cost effective. Therefore, the final MACT standard for new 
CEVs at major source facilities is 99.94 percent emission reduction. 
For the reasons explained above, our final MACT standards under CAA 
sections 112(d)(2) and (3) for both new and existing CEVs at major 
source facilities require these facilities to reduce the EtO emissions 
from new and existing CEVs by 99.94 percent.
    For existing CEVs 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 the CEVs, and the 
second option reflects applying a BMP to lower the in-chamber EtO 
concentration to 1 ppm before the chamber is opened (i.e., pollution 
prevention). With respect to the first option, because 34 out of 40 
area source facilities with CEVs already using controls to reduce CEV 
emissions, and we have no reason to believe that the other six cannot 
do the same, we consider emission controls to be generally available 
for existing CEVs at these facilities. Evaluating the available 
information on controls, including the documented control efficiency 
for 12 facilities in the category, we determined that a control 
efficiency of 99 percent is generally available for existing CEVs at 
area source facilities. The second potential GACT option we considered 
was the same management practice discussed in section IV.B.3.a of this 
preamble, which would require facilities to lower the in-chamber EtO 
concentration to 1 ppm before the chamber is opened. The impacts of 
these two options are presented in table 8.

[[Page 24110]]



 Table 8--Nationwide Emissions Reduction and Cost Impacts of Options Considered Under CAA Section 112(d)(5) for Existing CEVs at Area Source Facilities
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                   Total capital  Total annual costs ($/       EtO emission       Cost effectiveness ($/
               Option                     Proposed standard       investment ($)            yr)              reductions (tpy)            ton EtO)
--------------------------------------------------------------------------------------------------------------------------------------------------------
1..................................  99 percent emission              $1,750,000  $740,000..............  3.84 [7,680 lb/year]..  193,000 [$96/lb]
                                      reduction.
2..................................  BMP (estimated 20 percent                 0  $3,560,000 (one-time    0.796 [1,590 lb/year].  $4,470,000 [$2,240/lb]
                                      emission reduction).                         annual cost) \1\.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ This includes the cost for testing to verify that the new sterilization process will lower the in-chamber EtO concentration to 1 ppm before the
  chamber is opened, as well as preparing and submitting the necessary paperwork 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, and considering EtO is a highly 
potent carcinogen, 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. Such values include 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). We are 
finalizing 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 incur fewer annual costs than Option 2. 
Therefore, pursuant to CAA section 112(d)(5), we are finalizing Option 
1 for existing CEVs at area source facilities. Specifically, we are 
finalizing a requirement for these facilities to continuously reduce 
emissions from existing CEVs by 99 percent.
    For new CEVs at area source facilities, we considered two potential 
GACT options similar to those evaluated for existing CEVs at area 
source facilities. 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 IV.B.3.a, which 
would require facilities to lower the in-chamber EtO concentration to 1 
ppm before the chamber is opened. The impacts of these options, which 
are presented in table 9 of this preamble, are based on a model plant 
for new CEVs at a new area source facility with the following 
assumptions reflecting the average of each of the parameters at 
existing area source facilities:
     Annual EtO use: 100 tpy.
     Annual operating hours: 8,000.
     Portion of EtO going to CEVs: 1 percent.
     CEV flow rate: 200 cubic feet per second (cfs).
     Number of unique cycles: nine.

    Table 9--Nationwide Emissions Reduction and Cost Impacts of Options Considered Under CAA Section 112(d)(5) for New CEVs at Area Source Facilities
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                   Total capital  Total annual costs ($/       EtO emission       Cost effectiveness ($/
               Option                     Proposed standard       investment ($)            yr)              reductions (tpy)            ton EtO)
--------------------------------------------------------------------------------------------------------------------------------------------------------
1..................................  99 percent emission                $553,000  $142,000..............  0.99 [1,980 lb/year]..  $144,000 [$72/lb]
                                      reduction.
2..................................  BMP (estimated 20 percent                 0  $80,000 (one-time       0.20 [400 lb/year]....  $400,000 [$200/lb]
                                      emission reduction).                         annual cost) \1\.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ This includes the cost for testing to verify that the new sterilization process will lower the in-chamber EtO concentration to 1 ppm before the
  chamber is opened, 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, and considering EtO is a highly 
potent carcinogen, 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 than Option 2, and it is more cost-effective. 
Therefore, we are finalizing Option 1 as the standard for new CEVs at 
area source facilities under CAA section 112(d)(5). The standard 
requires these facilities to continuously reduce emissions from new 
CEVs by 99 percent.
    We have re-calculated the MACT floor for existing Group 1 room air 
emissions at major source facilities. We ranked the performance of the 
facilities with Group 1 room air emissions for which data are available 
based on percent emission reduction. There are only three performance 
tests that are currently available, only one of which contains three 
test runs. Therefore, the best performing 12 percent of facilities for 
which data are available consists of one facility with three test runs 
that is controlling its Group 1 room air emissions with a gas/solid 
reactor. That facility reported an emission reduction of 98 percent. We 
then used the LPL approach, as mentioned previously, to develop the 
MACT floor for existing sources. The LPL 1 value of the existing source 
MACT floor is 90 percent emission reduction. The outlet EtO 
concentration (UPL 99 value) that corresponds to this emission 
reduction is 93 ppbv. Since this is above 3xRDL, there are more 
stringent (i.e., BTF) options to consider. We considered two BTF 
options for reducing EtO emissions from this source: the first option 
we considered was 95 percent emission reduction. The first option 
reflects the lowest emission reduction that we have observed in 
performance tests, and The second option reflects the most stringent 
emission reduction for which compliance can be demonstrated. With 
respect to the second option, the most stringent emission reduction for 
which compliance can be demonstrated is that which corresponds to an 
outlet concentration of 30 ppbv (i.e., 3xRDL). This emission reduction 
is 97 percent, which is lower than two of the three reported values in 
the test runs that were used to calculate the MACT floor. The impacts 
of these options are presented in table 10 (along with the MACT floor 
impacts). Because we have

[[Page 24111]]

not identified any major source facilities with existing Group 1 room 
air emissions, the impacts are based on a model plant for existing 
Group 1 room air emissions at a synthetic area source facility with the 
following assumptions reflecting the average of each of the parameters 
at synthetic area source facilities:
     Annual EtO use: 140 tpy.
     Annual operating hours: 8,000.
     Portion of EtO going to Group 1 RAE: 0.4 percent.
     Group 1 room air emission flow rate: 400 cubic feet per 
second (cfs).

   Table 10--Nationwide Emissions Reduction and Cost Impacts of BTF Options Considered Under CAA Sections 112(d)(2) and 112(d)(3) for Group 1 Room Air
                                                          Emissions at Major Source Facilities
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                       Total capital   Total annual    EtO emission reductions   Cost effectiveness ($/
                Option                       Proposed standard        investment ($)   costs ($/yr)             (tpy)                   ton EtO)
--------------------------------------------------------------------------------------------------------------------------------------------------------
MACT floor...........................  90 percent emission reduction        $830,000        $176,000  0.168 [336 lb/year].....  $1,050,000 [$525/lb].
1....................................  95 percent emission reduction         553,000         129,000  2.80E-2 [56.0 lb/year]..  $4,610,000 [$2,300/lb].
2....................................  97 percent emission reduction         461,000         113,000  1.12E-2 [22.4 lb/year]..  $10,100,000 [$5,040/lb].
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Based on the estimates above, and considering EtO is a highly 
potent carcinogen, the cost-effectiveness numbers are within the range 
of the values that we have determined to be cost-effective for highly 
toxic HAPs. While both options are considered BTF under CAA sections 
112(d)(2), Option 2 would achieve greater emission reductions than 
Option 1. Therefore, the final MACT standard under CAA sections 
112(d)(2) and (3) for existing Group 1 room air emissions at major 
source facilities is 97 percent emission reduction.
    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 90 percent emission reduction. We considered the same 
BTF options as those evaluated for existing Group 1 room air emissions 
at major source facilities for the same reasons explained above. The 
first BTF option would require achieving 95 percent emission reduction, 
and the second BTF option would require achieving 97 percent emission 
reduction. The impacts of these options are presented in table 10 of 
this preamble. Because we have not identified any major source 
facilities with existing Group 1 room air emissions, the impacts are 
based on a model plant for new Group 1 room air emissions at a 
synthetic area source facility. Based on the estimates above, and 
considering EtO is a highly potent carcinogen, the cost-effectiveness 
numbers are within the range of the values that we have determined to 
be cost-effective for highly toxic HAPs. While both options are 
considered BTF under CAA sections 112(d)(2), Option 2 would achieve 
greater emission reductions than Option 1. Therefore, the final 
standard for new Group 2 room air emissions at major source facilities 
is 97 percent emission reduction. We also considered non-air quality 
health and environmental impacts and energy requirements when 
evaluating the BTF options. Further discussion of these considerations 
is presented in the document MACT Floor Analysis for Ethylene Oxide 
Commercial Sterilization--Chamber Exhaust Vents and Room Air Emission 
Sources--Promulgation Rule Review for the Ethylene Oxide Commercial 
Sterilization Source Category, available in the docket for this 
rulemaking.
    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 is the same BMP 
discussed above (lowering the in-chamber EtO concentration to 1 ppm 
before the chamber is opened). 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.\31\ We considered a 
standard of 80 percent emission reduction, which is the manufacturer 
guarantee for room air emissions controls provided by one of the 
commenters. We find this standard to be reasonable for existing Group 1 
room air emissions at area source facilities because it is the 
manufacturer guarantee, which means that it is a level of emission 
reduction that all sources can achieve. While some sources have 
demonstrated emission reductions higher than 80 percent, those 
reductions are limited to facilities with higher EtO usage rates, and 
we cannot determine whether smaller users of EtO can meet those 
emission reductions. The second potential GACT option we considered was 
the same management practice discussed in section IV.B.3.a, which would 
require facilities to lower the in-chamber EtO concentration to 1 ppm 
before the chamber is opened. During the sterilization process, EtO 
becomes trapped within the material and continues to off-gas after the 
sterilization process is complete. Therefore, if more EtO is driven out 
of the product prior to opening the chamber, this can lead to a 
reduction in post-sterilization EtO emissions, including those from 
pre-aeration handling of sterilized material. The impacts of these 
options are presented in table 11.
---------------------------------------------------------------------------

    \31\ The Group 1 room air emission reduction at these facilities 
ranges from 52 percent to 99.8 percent. It should be noted that the 
facility with the emission reduction at the upper bound of this 
range uses 135 tpy of EtO.

[[Page 24112]]



 Table 11--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
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                   Total capital  Total annual costs ($/       EtO emission       Cost effectiveness ($/
               Option                     Proposed standard       investment ($)            yr)              reductions (tpy)            ton EtO)
--------------------------------------------------------------------------------------------------------------------------------------------------------
1..................................  80 percent emission             $91,000,000  $12,900,000...........  3.66 [7,320 lb/year]..  $3,530,000 [$1,770/
                                      reduction.                                                                                   lb].
2..................................  BMP (estimated 20 percent                $0  $5,040,000 (one-time    1.13 [2,260 lb/year]..  $4,460,000 [$2,230/
                                      emission reduction).                         annual cost) \1\.                               lb].
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ This includes the cost for testing to verify that the new sterilization process will lower the in-chamber EtO concentration to 1 ppm before the
  chamber is opened, 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, and considering EtO is a highly 
potent carcinogen, 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 finalizing Option 1 because 
while both options are considered generally available under CAA section 
112(d)(5), Option 1 would achieve greater emission reduction than 
Option 2. Therefore, pursuant to CAA section 112(d)(5), we are 
finalizing Option 1 for existing Group 1 room air emissions at area 
source facilities. Specifically, we are finalizing a requirement for 
these facilities to continuously reduce emissions from existing Group 1 
room air emissions by 80 percent.
    For new Group 1 room air emissions at area source 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 reduction of 80 percent. The 
second potential GACT option we considered (Option 2) is a BMP that 
would require facilities to lower the in-chamber EtO concentration to 1 
ppm before the chamber is opened. The impacts of these options, which 
are presented in table 12 of this preamble, are based on a model plant 
for new Group 1 room air emissions at an area source facility with the 
assumptions reflecting the average of each of the parameters at area 
source facilities with new Group 1 room air emissions as described in 
section III.B.8.c of the proposal preamble.

 Table 12--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
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                   Total capital  Total annual costs ($/       EtO emission       Cost effectiveness ($/
               Option                     Proposed standard       investment ($)            yr)              reductions (tpy)            ton EtO)
--------------------------------------------------------------------------------------------------------------------------------------------------------
1..................................  80 percent emission                $922,000  $192,000..............  0.288 [576 lb/year]...  $666,000 [$333/lb].
                                      reduction.
2..................................  BMP........................               0  $80,000 (one-time       7.20E-2 [144 lb/year].  $1,110,000 [$556/lb].
                                     (estimated 20 percent                         annual cost) \1\.
                                      emission reduction).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ This includes the cost for testing to verify that the new sterilization process will lower the in-chamber EtO concentration to 1 ppm before the
  chamber is opened, 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 finalizing standards for new Group 1 room air emissions at area 
source facilities. Specifically, we are finalizing a requirement for 
these facilities to continuously reduce emissions from new Group 1 room 
air emissions by 80 percent.
    We re-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 
based on percent emission reduction. There are only three performance 
tests that are currently available, only one of which contains three 
test runs. Therefore, the best performing 12 percent of facilities for 
which data are available consists of one facility with three test runs 
that is controlling its Group 2 room air emissions with a gas/solid 
reactor. That facility reported an emission reduction of 96 percent. As 
mentioned previously, we then used the LPL approach to develop the MACT 
floor for existing sources. The LPL 1 value of the existing source MACT 
floor is 94 percent emission reduction. The outlet EtO concentration 
(LPL 1 value) that corresponds to this emission reduction is 10 ppbv. 
Since this is below 3xRDL, we adjusted the MACT floor by determining 
the emission reduction using 30 ppbv and the LPL 1 value of the inlet 
EtO concentration of the Group 2 room air emissions stream at the 
facility, which is 0.12 ppmv. This results in an adjusted MACT floor of 
86 percent emission reduction. Since this represents 3xRDL, there are 
no more stringent (i.e., BTF) options to consider, as there would be 
difficulty demonstrating compliance at any such lower limit. Therefore, 
the final MACT standard under CAA sections 112(d)(2) and (3) for 
existing Group 2 room air emissions at major source facilities is 86 
percent emission reduction.
    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

[[Page 24113]]

floor for existing sources. Therefore, the new source MACT floor is 
equivalent to the existing source MACT floor, which is 86 percent 
emission reduction. 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., BTF) options. Therefore, 
the proposed standard for new Group 2 room air emissions at major 
source facilities is 86 percent emission reduction.
    For existing Group 2 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 2 room air emissions, and the second option is the same BMP 
discussed above (lowering the in-chamber EtO concentration to 1 ppm 
before the chamber is opened). With respect to the first option, 30 out 
of 80 area source facilities with Group 2 room air emissions are 
already using controls to reduce those emissions.\32\ We considered a 
standard of 80 percent emission reduction, which is the manufacturer 
guarantee for room air emissions controls provided by one of the 
commenters. We find this standard to be reasonable for existing Group 2 
room air emissions at area source facilities because it is the 
manufacturer guarantee, which means that it is a level of emission 
reduction that all sources can achieve. While some sources have 
demonstrated emission reductions higher than 80 percent, those 
reductions are limited to facilities with higher EtO usage rates, and 
we cannot determine whether smaller users of EtO can meet those 
emission reductions. The second potential GACT option we considered was 
the same management practice discussed in section IV.B.3.a, which would 
require facilities to lower the in-chamber EtO concentration to 1 ppm 
before the chamber is opened. During the sterilization process, EtO 
becomes trapped within the material and continues to off-gas after the 
sterilization process is complete. Therefore, if more EtO is driven out 
of the product prior to opening the chamber, this can lead to a 
reduction in post-sterilization EtO emissions, including those from 
post-aeration handling of sterilized material. The impacts of these 
options are presented in table 13.
---------------------------------------------------------------------------

    \32\ The Group 2 room air emission reduction at these facilities 
ranges from 30 percent to 99.97 percent. It should be noted that the 
facility with the emission reduction at the upper bound of this 
range uses 135 tpy of EtO.

 Table 13--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
----------------------------------------------------------------------------------------------------------------
                                                                                  EtO emission         Cost
           Option                 Proposed      Total capital    Total annual      reductions     effectiveness
                                  standard     investment ($)    costs ($/yr)        (tpy)         ($/ton EtO)
----------------------------------------------------------------------------------------------------------------
1...........................  80 percent         $236,000,000  $32,700,000....  1.10 [2,200 lb/  $29,700,000
                               emission                                          year].           [$14,900/lb].
                               reduction.
2...........................  BMP (estimated                0  $5,440,000 (one- 0.311 [622 lb/   $17,500,000
                               20 percent                       time annual      year].           [$8,750/lb].
                               emission                         cost) \1\.
                               reduction).
----------------------------------------------------------------------------------------------------------------
\1\ This includes the cost for testing to verify that the new sterilization process will lower the in-chamber
  EtO concentration to 1 ppm before the chamber is opened, 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, and considering EtO is a highly 
potent carcinogen, 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. Further, as discussed in section 
III.B.8.g of the proposal preamble (88 FR 28790, April 13, 2023), there 
are multiple factors we consider in assessing the cost of the emission 
reductions. See NRDC v. EPA, 749 F.3d 1055, 1060 (D.C. Cir. April 18, 
2014) (``Section 112 does not command the 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 three percent. According to our 
estimates, the annual cost of the emission control option for most of 
the affected sources discussed above is well below three percent.\33\ 
However, reducing existing Group 2 room air emissions at area source 
facilities using emission control devices (Option 1), would 
significantly impact several companies operating a total of 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 three 
percent of revenue for these companies.\34\ 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, according to 
FDA, six of these facilities could impact the availability of the 
medical devices described in section I.A.1 of this preamble. Therefore, 
pursuant to CAA section 112(d)(5), we are finalizing Option 2 as the 
GACT standard for existing Group 2 room air emissions at area source 
facilities. Specifically, this GACT standard requires facilities to 
lower the in-chamber EtO concentration to 1 ppm before the chamber is 
opened.\35\
---------------------------------------------------------------------------

    \33\ 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.
    \34\ The issue of high cost-to-sales ratios is present only for 
this option and, thus, is not discussed for other options.
    \35\ As discussed in section IV.C.2.a.iii of this preamble, this 
GACT standard will ultimately apply only to facilities where EtO use 
is less than 4 tpy. Facilities where EtO use is at least 4 tpy will 
be required to meet an emission standard established under CAA 
section 112(f)(2).
---------------------------------------------------------------------------

    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 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 reduction of 80 percent. The 
second potential GACT option we considered (Option 2) is a BMP that 
would require facilities to lower the in-chamber EtO concentration to 1 
ppm before the chamber is opened. The impacts of these options, which 
are presented in table 14 of this preamble, are based on a model plant 
for new Group 2 room air emissions at an area source facility with the 
assumptions reflecting the average of each of the parameters at area 
source facilities with

[[Page 24114]]

new Group 1 room air emissions as described in section III.B.8.h of the 
proposal preamble.

Table 14--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
----------------------------------------------------------------------------------------------------------------
                                                                                  EtO emission         Cost
           Option                 Proposed      Total capital    Total annual      reductions     effectiveness
                                  standard     investment ($)    costs ($/yr)        (tpy)         ($/ton EtO)
----------------------------------------------------------------------------------------------------------------
1...........................  80 percent           $1,840,000  $332,000.......  3.6E-2 [72 lb/   $9,170,000
                               emission                                          year].           [$4,560/lb].
                               reduction.
2...........................  BMP (estimated                0  $40,000 (one-    9.1E-3 [18 lb/   $4,375,000
                               20 percent                       time annual      year].           [$2,190/lb].
                               emission                         cost)\1\.
                               reduction).
----------------------------------------------------------------------------------------------------------------
\1\ This includes the cost for testing to verify that the new sterilization process will lower the in-chamber
  EtO concentration to 1 ppm before the chamber is opened, 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, and considering EtO is a highly 
potent carcinogen, 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. As discussed earlier in this section, 
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). 
Although both options are considered generally available under CAA 
section 112(d)(5), Option 1 would achieve four times the emission 
reductions of Option 2. Therefore, pursuant to CAA section 112(d)(5), 
we are finalizing standards for new Group 2 room air emissions at area 
source facilities. Specifically, we are finalizing a requirement for 
these facilities to continuously reduce emissions from new Group 2 room 
air emissions by 80 percent.
c. PTE
    Comment: We received extensive comment on our proposal to require 
that each facility must operate areas with room air emissions subject 
to an emission standard under the PTE requirements of EPA Method 204. 
Some commenters were supportive of this requirement, stating that other 
regulatory bodies have already required this and that this is the 
correct protocol for ensuring that emissions are captured and routed to 
a control system. Other commenters were opposed to this requirement, 
stating that EPA Method 204 was established for smaller point source 
operations (e.g., paint booths, spray coating), as opposed to larger 
sterilization facilities. Several commenters cited other technical 
concerns, including the fact that not every facility is currently 
configured to meet the PTE requirements of EPA Method 204. The 
commenters suggested broad alternatives, including a simple requirement 
to operate areas with room air emissions subject to an emission 
standard under negative pressure.
    Response: We strongly disagree with the commenters that EPA Method 
204 is not appropriate to apply to this source category. The design 
requirements of EPA Method 204 are agnostic to the industry it is 
applied. It has been applied widely to any industrial processes that 
needs to control VOC emissions, including several existing commercial 
sterilizers that have already been complying with EPA Method 204. In 
order to meet the emission standards, it is necessary to ensure that 
all emissions are captured and routed to a control system. Our 
established protocol in numerous new source performance standards, 
NESHAPs, and federally enforceable State and local programs (e.g., 
title V permits, State implementation plans) for ensuring complete 
capture of room air emissions is EPA Method 204. We recognize that many 
commercial sterilizers will need to retrofit their facilities to meet 
the PTE requirements of EPA Method 204, similar to facilities that have 
already done so. We have accounted for the cost to retrofit facilities 
by scaling the cost from a large facility that conducted a retrofit. 
Furthermore, based on our knowledge regarding the application of EPA 
Method 204 in general, retrofitting to meet this method can be 
complicated, depending on the size of the facility. However, commercial 
sterilization facilities tend to be simple buildings (in some cases, 
re-purposed warehouses) with a relatively small footprint, which helps 
the retrofitting process. The emission standards for room air emissions 
that we evaluated assume 100 percent capture of EtO emissions,\36\ and 
the costs of complying with the PTE requirements of EPA Method 204 were 
included in our BTF and GACT evaluations. We found each emission 
standard that we evaluated to be cost-effective (see section IV.B.3.b 
of this preamble for more information). In addition, the term 
``negative pressure'' is vague and can imply any capture efficiency 
between zero and 100 percent. The commenters did not provide specific 
suggestions for alternative capture efficiencies, nor did they provide 
the criteria that would be used to demonstrate that those efficiencies 
are being met, and we are unable to evaluate alternative negative 
pressure requirements as a result. Therefore, EPA Method 204 is 
appropriate to apply to this source category in order to ensure 
complete capture of room air emissions.
---------------------------------------------------------------------------

    \36\ Section 2 of EPA Method 204 states, in part, ``If the 
criteria are met and if all the exhaust gases from the enclosure are 
ducted to a control device, then the volatile organic compounds 
(VOC) capture efficiency (CE) is assumed to be 100 percent, and CE 
need not be measured.''
---------------------------------------------------------------------------

    Comment: Several commenters requested various flexibilities and 
clarifications with respect to the PTE requirements of EPA Method 204. 
Several commenters expressed concern with Criterion 5.1 of EPA Method 
204, stating that it would not be possible to always ensure that doors 
are ``at least four equivalent opening diameters'' from all EtO storage 
media or post-aeration sterilized product, particularly during loading 
and unloading operations. Two commenters recommended that we revise the 
standards to permit implementation of cascading air systems to capture 
room air emissions.\37\ One commenter stated that these systems would 
provide greater flexibility to accommodate sterilization operations 
that could not implement a PTE, would offer EtO capture and control 
efficiency that was as effective as a PTE, and would have fewer 
manufacturing implications and potential adverse impacts. Finally, two

[[Page 24115]]

commenters expressed concern with Criteria 5.2, 5.3, and 5.5 of EPA 
Method 204.
---------------------------------------------------------------------------

    \37\ These are systems that move air from ambient pressure, 
through warehouse ventilation, secondary aeration, primary aeration, 
the sterilizer chamber, and ultimately to an air pollution control 
device to capture and control EtO emissions. This is opposed to 
other systems where air from one source is captured and then 
directly sent to a control system.
---------------------------------------------------------------------------

    Response: Criterion 5.1 of EPA Method 204 states that ``Any natural 
draft opening (NDO) shall be at least four equivalent opening diameters 
from each VOC emitting point unless otherwise specified by the 
Administrator.'' \38\ We disagree with the commenters' concerns that 
Criterion 5.1 of EPA Method 204 will not be possible to meet for doors 
where either EtO storage media is moved into a PTE or post-aeration 
sterilized material is moved out of a PTE. There may be certain 
facility designs where such an exemption is either necessary or 
unnecessary in order to ensure complete capture of room air emissions. 
However, the EPA does not have enough information to make that 
determination for all facilities within the source category as part of 
this rulemaking. Criterion 5.1 of EPA Method 204 allows delegated 
authorities to exempt any NDO from this requirement, as needed. 
Therefore, we are not exempting Criterion 5.1 of EPA Method 204 for 
doors where either EtO storage media is moved into a PTE or post-
aeration sterilized material is moved out of a PTE as part of this 
final rule. Instead, we are relying on the delegated authorities to 
make that determination for their commercial sterilization facilities, 
as provided in Criterion 5.1., as they are in a better place to 
determine whether there are sufficient measures in place to capture any 
emission points within four equivalent opening diameters of an NDO. 
With respect to cascading air systems, we disagree with the commenters' 
suggestion that they be permitted in place of the PTE requirements of 
EPA Method 204, as they are insufficient on their own to ensure 
complete capture of room air emissions. However, it is not our intent 
to discourage or prohibit the use of these systems altogether. 
Cascading air systems may be used to capture and route room air 
emissions to a control device. However, in order to ensure complete 
capture of room air emissions, if such a system contains one or more 
areas that are subject to the PTE requirements of EPA Method 204, then 
the entire system must be treated as a single enclosure that is subject 
to those requirements.
---------------------------------------------------------------------------

    \38\ Per 40 CFR 51.100(s), EtO is a VOC.
---------------------------------------------------------------------------

    For all other flexibilities suggested by the commenters, we provide 
the following responses:
     Criterion 5.2 of EPA Method 204 states that ``Any exhaust 
point from the enclosure shall be at least four equivalent duct or hood 
diameters from each NDO.'' One commenter stated that Criterion 5.2 may 
not be possible for all facilities due to preexisting layouts. This 
criterion only applies to temporary total enclosures, as opposed to 
PTEs, and is not required in the final rule.
     Criterion 5.3 of EPA Method 204 states that ``The total 
area of all NDO's shall not exceed 5 percent of the surface area of the 
enclosure's four walls, floor, and ceiling.'' One commenter stated that 
the presence of garage doors could exceed the requirement that NDOs not 
exceed five percent of the PTE total floor space. However, we note that 
facilities can be, and have been, re-designed in order to meet the PTE 
requirements of EPA Method 204, including Criterion 5.3. Therefore, we 
are not finalizing any exceptions for this criterion.
     Criterion 5.5 of EPA Method 204 states that ``All access 
doors and windows whose areas are not included in section 5.3 and are 
not included in the calculation in section 5.4 shall be closed during 
routine operation of the process''. Two commenters expressed concern 
with Criterion 5.4 of EPA Method 204. However, the commenters did not 
provide any explanation as to why exceptions for Criterion 5.5 of EPA 
Method 204 should be made. Therefore, we are not finalizing any 
exceptions for this criterion.
d. Warehouses
    Comment: We received extensive comments on the regulation of 
warehouses, particularly stand-alone (i.e., off-site) warehouses. Most 
commenters were supportive of regulating emissions from all warehouses, 
stating that sterilized materials can continue to off-gas significant 
quantities of EtO after being moved to a warehouse. Several commenters 
pointed to a stand-alone warehouse in Georgia, where the State 
estimated that potential pre-control EtO emissions were approximately 
5,000 lb/year. One commenter was opposed to including standards for 
stand-alone warehouses as part of this final rule, stating that we 
could, instead, identify potentially applicable facilities, collect 
data from these facilities, and then determine if further regulation is 
necessary.
    Response: It is our understanding that there are three types of 
warehouses within this industry: attached warehouses, co-located 
warehouses, and stand-alone warehouses. Attached warehouses are those 
that are part of an EtO sterilization building. Co-located warehouses 
are those that are detached from but ``contiguous'' (including 
adjacent) to and ``under common control'' with the EtO sterilization 
building, including leased properties.\39\ Stand-alone warehouses are 
those that are not attached to or co-located with an EtO sterilization 
building. According to our record at the time of category listing, 
``the Commercial Sterilization Facilities source category includes 
``facilities which use ethylene oxide in any equipment which destroys 
bacteria, viruses, fungi, insects, or other unwanted microorganisms or 
materials when such facilities are engaged in the growth, manufacture, 
construction, transportation, retail or wholesale trade, or storage of 
commercial products, or when such facilities are engaged in the 
operation of museums, art galleries, arboreta, or botanical or 
zoological gardens or exhibits. Not included in this category are 
hospitals, doctor offices, veterinary offices, clinics, and other 
facilities where medical services are rendered'' (emphasis added).\40\ 
Under this definition, warehouses that are part of facilities which use 
EtO, including attached and co-located warehouses, are part of the 
source category and, therefore, subject to the standards for Group 2 
room air emissions. However, because stand-alone warehouses do not use 
EtO, they are not included in the source category definition. 
Furthermore, we do not have sufficient information to understand where 
these warehouses are located, who owns them, how they are operated, or 
what level of emissions potential they may have. While several 
commenters note that emissions information is available for at least 
one stand-alone warehouse, it is unknown whether the emissions 
information for this facility is representative of all stand-alone 
warehouses. Thus, standards for these facilities are not included as 
part of this final rule. However, as suggested by one commenter, we are 
planning to gather information from stand-alone warehouses as soon as 
possible to

[[Page 24116]]

understand what the source category looks like and its emission 
potential and, if necessary, develop a regulatory action that both 
lists a new source category and proposes standards for stand-alone 
warehouses handling EtO sterilized medical devices. This information 
gathering effort may include engaging with State and local agencies and 
non-governmental organizations, as well as conducting an ICR(s) 
pursuant to CAA section 114.
---------------------------------------------------------------------------

    \39\ This final rule establishes standards under CAA section 112 
for both major and area sources of commercial sterilization 
facilities. As the EPA explained in its final rule promulgating the 
General Provisions for NESHAP pursuant to section 112, ``[f]or the 
purposes of implementing section 112, the major/area source 
determination is made on a plant-wide basis; that is, HAP emissions 
from all sources located within a contiguous area and under common 
control are considered in the determination.'' 59 FR 12408, 12411 
(March 16, 1994). The EPA noted that ``the common dictionary term 
``contiguous'' consists, in part, of ``nearby, neighboring, 
adjacent,'' and that ``the EPA has historically interpreted 
`contiguous property' to mean the same as `contiguous or adjacent 
property' in the development of numerous regulations to implement 
the Act.'' Id. at 12412.
    \40\ Documentation for Developing the Initial Source Category 
List, Final Report, page A-83 (see EPA-450/3-91-030, July 1992).
---------------------------------------------------------------------------

    The remaining comments and our specific responses can be found in 
the document, Summary of Public Comments and Responses for the Risk and 
Technology Review for Commercial Sterilization Facilities, available in 
the docket for this rulemaking.
4. What is the rationale for our final approach and final decisions for 
the revisions pursuant to CAA section 112(d)(2), 112(d)(3), and 
112(d)(5)?
    We evaluated the comments on our proposed 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, as well as our proposed technical correction to the emission 
standard for ARVs at facilities where EtO use is at least 10 tpy. As 
explained above in section IV.B.3 and in Chapter 4 of the document, 
Summary of Public Comments and Responses for the Risk and Technology 
Review for Commercial Sterilization Facilities, we made changes in the 
final rule based on comments received during the proposed rulemaking. 
More information and rationale concerning all the amendments we are 
finalizing pursuant to CAA sections 112(d)(2), 112(d)(3), and 112(d)(5) 
is in the preamble to the proposed rule (88 FR 22790, April 13, 2023), 
in section IV.B.3 of this preamble, and in the comments and our 
specific responses to the comments in the document, Summary of Public 
Comments and Responses for the Risk and Technology Review for 
Commercial Sterilization Facilities, which is available in the docket 
for this rulemaking. Therefore, we are finalizing the proposed 
standards for SCVs and ARVs at facilities where EtO use is less than 1 
tpy, finalizing the proposed standards for ARVs at facilities where EtO 
use is at least 1 tpy but less than 10 tpy, finalizing standards for 
CEVs, finalizing the proposed emission standards for room air emissions 
at major sources facilities, finalizing emission standards for room air 
emissions at area source facilities, and finalizing the proposed 
revisions for ARVs at facilities where EtO use is at least 10 tpy.

C. Residual Risk Review for the Commercial Sterilization Facilities 
Source Category

1. What did we propose pursuant to CAA section 112(f) for the 
Commercial Sterilization Facilities source category?
    Pursuant to CAA section 112(f), we conducted a residual risk review 
and presented the results of this review, along with our proposed 
decisions regarding risk acceptability and ample margin of safety, in 
the April 13, 2023, proposed rule for 40 CFR part 63, subpart O (88 FR 
22790). The results of the risk assessment for the proposal are 
presented briefly in table 15 of this preamble. As discussed in section 
III.A of the proposed rule, all baseline risk results were developed 
using the best estimates of actual emissions, and we did not conduct a 
separate assessment of allowables at proposal. More detail is in the 
residual risk technical support document, Residual Risk Assessment for 
the Commercial Sterilization Facilities Source Category in Support of 
the 2023 Risk and Technology Review Proposed Rule, which is available 
in the docket for this rulemaking (see Docket Item No. EPA-HQ-OAR-2019-
0178-0482).

                     Table 15--Commercial Sterilization Facilities Source Category Baseline Risk Assessment Results in the Proposal
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                               Estimated population at         Estimated
                                             Maximum          increased risk of cancer       annual cancer                      Maximum screening acute
        Number of facilities \1\            individual   ----------------------------------    incidence     Maximum chronic   noncancer hazard quotient
                                         cancer risk (in     >100-in-1      [gteqt]1-in-1      (cases per    noncancer TOSHI             (HQ)
                                          1 million) \2\      million          million           year)
--------------------------------------------------------------------------------------------------------------------------------------------------------
97 \3\.................................           6,000           18,000        8,300,000              0.9             0.04   0.002 (REL).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Number of facilities evaluated in the risk analysis.
\2\ Maximum individual excess lifetime cancer risk due to HAP emissions from the source category.
\3\ As part of the risk assessment for the proposed rulemaking, there were 86 facilities in the Commercial Sterilization Facilities source category 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 was a lack of certainty over whether these were 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 had low risk.

    The results of the proposed chronic baseline inhalation cancer risk 
assessment at proposal indicated that, based on estimates of current 
actual emissions, the MIR posed by the source category was 6,000-in-1 
million. At proposal, the total estimated cancer incidence from this 
source category was estimated to be 0.9 excess cancer cases per year, 
or one case in every 1.1 years. Approximately 8.3 million people were 
estimated to have cancer risks at or above 1-in-1 million from HAP 
emitted from the facilities in this source category. At proposal, the 
estimated maximum chronic noncancer target organ-specific hazard index 
(TOSHI) for the source category was 0.04, indicating low likelihood of 
adverse noncancer effects from long-term inhalation exposures.
    As shown in table 15 of this preamble, the acute risk screening 
assessment of reasonable worst-case inhalation impacts indicates a 
maximum acute HQ of 0.002 for propylene oxide based on the reference 
exposure level (REL) acute health reference value.\41\ For EtO, the 
maximum HQ is 0.0005 based on the acute exposure guideline level 
(AEGL)-2 acute health reference value.\42\
---------------------------------------------------------------------------

    \41\ Not to be confused with the ``recommended exposure limit'', 
which is used by the National Institute for Occupational Safety and 
Health.
    \42\ Acute RELs, ERPG-1, and AEGL-1 acute health reference 
values are not available for ethylene oxide.
---------------------------------------------------------------------------

    At proposal, the maximum lifetime individual cancer risk posed by 
the 97 modeled facilities, based on whole facility emissions, was 
6,000-in-1 million, with EtO emissions from SCVs and Group 2 room air 
emissions from the Commercial Sterilization Facilities source category 
driving the risk. Regarding the noncancer risk

[[Page 24117]]

assessment, the maximum chronic noncancer TOSHI posed by whole facility 
emissions was estimated to be 0.04 (for the neurological system as the 
target organ), driven by emissions of EtO from source category sources.
    We weighed all health risk factors, including those shown in table 
15 of this preamble, in our risk acceptability determination and 
proposed that the risks posed by this source category under the current 
provisions are unacceptable. At proposal, we identified several options 
to control EtO emissions from SCVs and Group 2 room air emissions.
    To reduce risks, we considered two additional control options after 
implementation of controls under CAA sections 112(d)(2), 112(d)(3), and 
112(d)(5). Control Option 1 would have required a 99.94 percent 
emission reduction standard for SCVs at facilities where EtO use is at 
least 40 tpy, as well as a 2.8 E-3 lb/h standard for existing Group 2 
room air emissions at area source facilities where EtO use is at least 
20 tpy. We determined that this would have resulted in a source 
category MIR of 400-in-1 million. Control Option 2 would have imposed 
the same requirements as Control Option 1, but it would also have 
required facilities where the MIR is greater than 100-in-1 million 
after Control Option 1 is imposed to limit their existing Group 2 room 
air emissions to a maximum volumetric flow rate of 2,900 dscfm and a 
maximum EtO concentration of 30 ppbv. This would have resulted in a 
source category MIR of 100-in-1 million. We proposed Control Option 2 
and solicited comment on Control Option 1.
    We proposed that, after implementation of the proposed controls for 
SCVs and Group 2 room air emissions at commercial sterilization 
facilities, the resulting risks would be acceptable for this source 
category. In our proposal, we presented the risk impacts using health 
risk measures and information, including the MIR, cancer incidence, and 
associated uncertainty in emissions estimates after application of the 
proposed options to control EtO emissions from Group 2 room air 
emissions (88 FR 22790, April 13, 2023). At proposal, we determined 
application of the controls for SCVs and Group 2 room air emissions 
would reduce the estimated MIR from 6,000-in-1 million to 100-in-1 
million.
    We then considered whether the standards provide an ample margin of 
safety to protect public health and whether, taking into consideration 
costs, energy, safety, and other relevant factors, additional standards 
are required to prevent an adverse environmental effect. To determine 
whether the rule provides an ample margin of safety, we considered the 
requirements that we proposed to achieve acceptable risks. In addition, 
we considered more stringent controls for SCVs, as well as expanding 
the emission standard and work practice standards for existing Group 2 
room air emissions to all facilities in the source category. In 
considering whether the standards should be tightened to provide an 
ample margin of safety to protect public health, we considered the same 
risk factors that we considered for our acceptability determination and 
also examined the costs, technological feasibility, and other relevant 
factors related to emissions control options that might reduce risk 
associated with emissions from the source category. Based on these 
considerations, we proposed that the standards that we proposed to 
achieve acceptable risks, along with a 99.94 percent emission reduction 
standard for SCVs at facilities where EtO use is at least 10 tpy but 
less than 40 tpy and a 99.8 percent emission reduction standard for 
SCVs at facilities where EtO use is at least 1 tpy but less than 10 
tpy, would provide an ample margin of safety to protect public health 
(section III.D.2 of the proposal preamble, 88 FR 22790, April 13, 
2023). We also solicited comment on which of the available control 
options should be applied in order to provide an ample margin of safety 
to protect public health.
2. How did the risk review change for the Commercial Sterilization 
Facilities source category?
a. Commercial Sterilization Facilities Source Category Risk Assessment 
and Determination of Risk Acceptability (Step 1)
    As part of the final risk assessment, the EPA reanalyzed risks to 
include allowable emissions (which we did not include at the proposal 
stage), changes since proposal to certain emission standards being 
finalized for previously unregulated sources, and three additional 
facilities identified by commenters. Allowable emissions are the 
maximum amount that facilities are allowed to emit under CAA section 
112(d) standards. For previously unregulated sources, since there were 
no CAA section 112(d) standards in place, the allowable emissions in 
the baseline risk assessment are equal to the uncontrolled emissions 
from these sources. In some instances, the actual emissions for these 
sources are lower than the allowable emissions. This is because some 
facilities are already controlling these sources as a result of local 
requirements or through voluntary control measures.\43\ The revised 
emissions used to reanalyze risks are available in the docket for this 
rulemaking (see section IV.C.3 of this preamble and Appendix 1 of the 
Residual Risk Assessment for the Commercial Sterilization Facilities 
Source Category in Support of the 2024 Risk and Technology Review Final 
Rule).
---------------------------------------------------------------------------

    \43\ As discussed later in this section, for previously 
unregulated sources, the allowable emissions in the risk assessment 
that considers controls we are promulgating under CAA sections 
112(d)(2), 112(d)(3), and 112(d)(5) are equal to the controlled 
emissions from these sources assuming that they are only controlled 
to the degree that we are requiring pursuant to CAA sections 
112(d)(2), 112(d)(3), and 112(d)(5). In some instances, the actual 
emissions for these sources may still be lower than the allowable 
emissions. This is because some facilities are already controlling 
these sources to a degree greater than what we are finalizing 
pursuant to CAA sections 112(d)(2), 112(d)(3), and 112(d)(5) as a 
result of local requirements or through voluntary control measures.
---------------------------------------------------------------------------

    Based on the actual emission estimates, the results of the chronic 
inhalation cancer risk from the risk assessment indicate that the 
maximum lifetime individual cancer risk posed by the 88 facilities 
could be as high as 6,000-in-1 million, with EtO as the major 
contributor to the risk. The total estimated cancer incidence from the 
revised risk assessment is 0.9 excess cancer cases per year, or one 
excess case in every 1.1 years. Of the approximately 115 million people 
that live within 50 kilometers (km) of the 88 facilities included in 
the risk assessment, 8.5 million people were estimated to have cancer 
risks greater than or equal to 1-in-1 million from HAP emitted from the 
facilities in this source category, and approximately 19,000 are 
estimated to have cancer risks greater than 100-in-1 million (table 16 
of this preamble).
    The estimated maximum chronic noncancer TOSHI for the source 
category remained unchanged from the proposal at 0.04, indicating low 
likelihood of adverse noncancer effects from long-term inhalation 
exposures. Additionally, the worst-case acute HQ remained unchanged 
from proposal (0.002 for propylene oxide based on the REL acute health 
reference value).
    The maximum lifetime individual cancer risk based on whole facility 
emissions was 6,000-in-1 million driven by EtO emissions from the 
Commercial Sterilization Facilities source category. The maximum 
chronic noncancer TOSHI posed by whole facility emissions was estimated 
to be 0.04 (for the neurological system as the target organ), driven by 
emissions of EtO from source category sources.

[[Page 24118]]

    Based on allowable emission estimates, the maximum lifetime 
individual cancer risk could be as high as 8,000-in-1 million, with EtO 
driving the risk. The total estimated cancer incidence is 8 excess 
cancer cases per year, or 1 excess case in every 1.5 months. 
Approximately 62 million people were estimated to have cancer risks 
greater than or equal to 1-in-1 million from allowable emissions, and 
approximately 260,000 are estimated to have cancer risks greater than 
100-in-1 million (table 16 of this preamble).

         Table 16--Commercial Sterilization Facilities Source Category Baseline Risk Assessment Results Based on Revised Emissions in Final Rule
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                Maximum         Estimated population at        Estimated
                                              individual       increased risk of cancer      annual cancer      Maximum
         Number of facilities \1\             cancer risk  --------------------------------    incidence        chronic        Maximum screening acute
                                            (in 1 million)     >100-in-1     [gteqt]1-in-1    (cases per       noncancer            noncancer HQ
                                                  \2\           million         million          year)           TOSHI
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                    Actual Emissions
--------------------------------------------------------------------------------------------------------------------------------------------------------
88 \3\....................................           6,000          19,000       8,500,000             0.9            0.04  0.002 (REL).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                   Allowable Emissions
--------------------------------------------------------------------------------------------------------------------------------------------------------
88 \3\....................................           8,000         260,000      62,000,000               8            0.05  ............................
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Number of facilities evaluated in the risk analysis.
\2\ Maximum individual excess lifetime cancer risk due to HAP emissions from the source category.
\3\ Two of the 90 facilities identified in the source category are planned or under construction and therefore were not included in the risk assessment.

    Risks were then estimated after application of the controls 
finalized in this rulemaking pursuant to CAA sections 112(d)(2), 
112(d)(3), and 112(d)(5). A summary of those controls is presented in 
table 17.

Table 17--Summary of Standards After Taking 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 and new..  At least 10 tpy...  99 percent          Current standard.
                                                                           emission
                                                                           reduction.
                                                      At least 1 but      99 percent          Current standard.
                                                       less than 10 tpy.   emission
                                                                           reduction.
                                                      Less than 1 tpy...  99 percent          112(d)(5).
                                                                           emission
                                                                           reduction.
ARV.............................  Existing and new..  At least 10 tpy...  99 percent          Current standard.
                                                                           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.
CEV at major sources............  Existing and new..  N/A...............  99.94 percent       112(d)(2) and
                                                                           emission            112(d)(3).
                                                                           reduction \1\.
CEV at area sources.............  Existing and new..  N/A...............  99 percent          112(d)(5).
                                                                           emission
                                                                           reduction \1\.
Group 1 room air emissions at     Existing and new..  N/A...............  97 percent          112(d)(2) and
 major sources.                                                            emission            112(d)(3).
                                                                           reduction \1\ \2\.
Group 1 room air emissions at     Existing and new..  N/A...............  80 percent          112(d)(5).
 area sources.                                                             emission
                                                                           reduction \1\ \2\.
Group 2 room air emissions at     Existing and new..  N/A...............  86 percent          112(d)(2) and
 major sources.                                                            emission            112(d)(3).
                                                                           reduction \1\ \2\.
Group 2 room air emissions at     Existing..........  N/A...............  Lower the EtO       112(d)(5).
 area sources.                                                             concentration
                                                                           within each
                                                                           sterilization
                                                                           chamber to 1 ppm
                                                                           before the
                                                                           chamber can be
                                                                           opened.\1\
                                  New...............  N/A...............  80 percent          112(d)(5).
                                                                           emission
                                                                           reduction \1\ \2\.
----------------------------------------------------------------------------------------------------------------
\1\ This standard is different from what was proposed.
\2\ To assure compliance with the emission limit, we are requiring 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.

    Based on the risk assessment considering controls finalized under 
CAA sections 112(d)(2), 112(d)(3), and 112(d)(5), the maximum lifetime 
individual cancer risk could be as high as 6,000-in-1 million, with EtO 
driving the risk. For previously unregulated sources, the allowable 
emissions in this risk assessment are equal to the controlled emissions 
from these sources assuming that they are only controlled to the degree 
that we are requiring pursuant to CAA sections 112(d)(2), 112(d)(3), 
and 112(d)(5). In some instances, the actual emissions for these 
sources may still be lower than the allowable emissions. This is 
because some facilities are already controlling these sources to a 
degree greater than what we are finalizing pursuant to CAA sections 
112(d)(2), 112(d)(3), and 112(d)(5) as a result of local requirements 
or through voluntary control measures. The total estimated

[[Page 24119]]

cancer incidence could be as high as 4 excess cancer cases per year, or 
1 excess case in every 3 months. As many as 38 million people are 
estimated to have cancer risks greater than or equal to 1-in-1 million, 
and approximately 85,000 people are estimated to have cancer risks 
greater than 100-in-1 million (table 18 of this preamble).
    However, as noted above, some facilities are currently performing 
better than the controls finalized under CAA sections 112(d)(2), 
112(d)(3), and 112(d)(5), and in that case we estimate the maximum 
lifetime individual cancer risk as 5,000-in-1 million, with EtO driving 
the risk. The total estimated cancer incidence is estimated to be 0.4 
excess cancer cases per year, or 1 excess case in every 2.5 years. 
Approximately 4.2 million people were estimated to have cancer risks 
greater than or equal to 1-in-1 million, and approximately 3,900 are 
estimated to have cancer risks greater than 100-in-1 million (table 18 
of this preamble), based only on the application of the CAA section 
112(d)(2), 112(d)(3), and 112(d)(5) actions being finalized.

 Table 18--Commercial Sterilization Facilities Source Category Risk Assessment Results Based on Emissions After
                       Controls Promulgated Under CAA Sections 112(d)(2)-(3) and 112(d)(5)
----------------------------------------------------------------------------------------------------------------
                                                                    Estimated population at         Estimated
                                                  Maximum        increased risk of cancer \2\     annual cancer
          Number of facilities \1\               individual   ----------------------------------    incidence
                                              cancer risk (in     >100-in-1      [gteqt]1-in-1      (cases per
                                               1 million) \2\      million          million         year) \2\
----------------------------------------------------------------------------------------------------------------
88 \3\......................................  \4\ 5,000-6,000      \4\ 3,900-   \4\ 4,200,000-        \4\ 0.4-4
                                                                      260,000       62,000,000
----------------------------------------------------------------------------------------------------------------
\1\ Number of facilities evaluated in the risk analysis.
\2\ Maximum individual excess lifetime cancer risk due to HAP emissions from the source category.
\3\ Two of the 90 facilities identified in the source category are planned or under construction and therefore
  were not included in the risk assessment.
\4\ Ranges in values account for if all facilities were performing at the level of the standards (high end) to
  considering facilities that are currently performing better than the standards (low end).

    Based on the revised risk assessment results considering controls 
finalized under CAA sections 112(d)(2), 112(d)(3), and 112(d)(5), we 
continue to find that the risks are unacceptable, as we did during the 
proposal due to emissions of EtO from SCVs, ARVs, Group 1 room air 
emission, Group 2 room air emissions, and CEVs. Pursuant to CAA section 
112(f)(2), the EPA must first determine the emission standards 
necessary to reduce risks to an acceptable level, and then determine 
whether further HAP emissions reductions are necessary to provide an 
ample margin of safety to protect public health or to prevent, taking 
into consideration costs, energy, safety, and other relevant factors, 
an adverse environmental effect. Immediately below is a discussion of 
the standards the EPA has evaluated for bringing risks to an acceptable 
level (step 1).
i. SCV Emissions
    There are 26 facilities within the source category where the 
``revised allowable emissions'' from SCVs (i.e., allowable emissions 
after implementing existing and newly promulgated 112(d) standards in 
this final rule) contribute to the facilities' MIRs exceeding 100-in-1 
million, and EtO usage at these facilities ranges from four tpy to 446 
tpy. The previous subpart O required 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 final standard under CAA section 
112(d)(5) for the previously unregulated SCVs, which were those at 
facilities where EtO use is less than 1 tpy (see section IV.B.2).
    Our data do not identify any add-on controls beyond those we have 
already considered when promulgating or reviewing the SCV standards in 
the previous subpart O or finalizing the standards for the previously 
unregulated SCVs in section IV.B. However, our evaluation of the 
performance test data and manufacturer guarantees shows that these 
controls can achieve greater than 99 percent reduction. We therefore 
considered more stringent SCV standards for facilities where EtO use is 
at least 1 tpy, which would include all 26 facilities where the revised 
allowable emissions from SCVs contribute to the facilities' MIRs 
exceeding 100-in-1 million.
    We evaluated 99.8 percent reduction of SCV emissions from 
facilities using at least 1 tpy but less than 10 tpy of EtO.\44\ As 
discussed in section III.D.2 of the proposal preamble (88 FR 22790, 
April 13, 2023), 99.8 percent is the maximum emission reduction from 
SCV with which compliance can be demonstrated at all facilities with 
EtO usage within this range.\45\ A 99.8 percent reduction would 
eliminate SCV emissions as a contributor to a facility's MIR exceeding 
100-in-1 million for facilities using at least 1 tpy but less than 10 
tpy of EtO.\46\ We have determined that a 99.8 percent emission 
reduction standard is feasible because of one commenter's statement 
that, based on their discussions with control device manufacturers, the 
best and most advanced technologies will be guaranteed to meet a 99.9 
percent emission reduction standard for SCVs.
---------------------------------------------------------------------------

    \44\ The MIRs of facilities with EtO usage less than 1 tpy are 
all below 100-in-a-million.
    \45\ 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 (which 
is 3 x RDL).
    \46\ A facility with usage amount in this range may still have a 
MIR exceeding 100-in-a-million due to other emissions.
---------------------------------------------------------------------------

    For facilities using at least 10 tpy, further reduction would be 
needed to eliminate SCV emissions as a contributor to a facility's MIR 
exceeding 100-in-a-million. We evaluated 99.9 percent reduction, which 
as mentioned above reflects the manufacturer guaranteed control level. 
A 99.9 percent reduction would eliminate SCV emissions as a contributor 
to facilities' MIRs exceeding 100-in-1 million for facilities using at 
least 10 tpy but less than 30 tpy of EtO. As discussed in section 
III.D.2 of the proposal preamble (88 FR 22790, April 13, 2023), we 
evaluated a 99.94 percent emission reduction standard for these 
facilities as part of Control Option A under the second step of the 
residual risk review. However, as discussed in section IV.C.3 of this 
preamble, several commenters stated that we do not have representative 
performance tests for SCVs. While this is not true for the whole source 
category, it is true for facilities where EtO use is at least 10 tpy 
but less than 30 tpy. Therefore, as part of this final rule, we did not 
evaluate an

[[Page 24120]]

emission reduction standard more stringent than the manufacturer 
guarantee for SCVs at these facilities.
    For facilities using at least 30 tpy, further reduction would be 
needed to eliminate SCV emissions as a contributor to a facility's MIR 
exceeding 100-in-1 million. We evaluated 99.99 percent reduction based 
on a performance test showing this level of reduction from a facility 
within this group. A 99.99 percent reduction would eliminate SCV 
emissions as a contributor to a facility's MIR exceeding 100-in-a-
million for facilities using at least 30 tpy of EtO. We received 
comment on the technical feasibility of emission standards that exceed 
the manufacturer guarantee for SCVs (i.e., 99.9 percent emission 
reduction), but we do not have any information suggesting that any 
facility within this group cannot achieve 99.99 percent emission 
reduction. See section IV.C.3 of this preamble for more information.
ii. ARV Emissions
    There are three facilities where revised allowable ARV emissions 
contribute to the facility's MIR exceeding 100-in-1 million, and EtO 
use at these facilities currently ranges from 44 tpy to 446 tpy of EtO. 
The previous subpart O required a 1 ppm maximum outlet concentration or 
99 percent emission reduction for ARVs at facilities where EtO use is 
at least 10 tpy. As discussed in section IV.B, we are removing the 1 
ppm maximum outlet concentration alternative standard, and we are 
finalizing 99 percent emission reduction standards under CAA section 
112(d)(5) for previously unregulated ARVs, which were those at 
facilities where EtO use is less than 10 tpy. As a result, the final 
112(d) standard for ARV emissions at all facilities is 99 percent 
reduction.
    Our data do not identify any add-on controls beyond those we have 
already considered when promulgating, or proposing revisions to the 
previous ARV standards in subpart O or finalizing the standards for the 
previously unregulated ARVs in section IV.B. However, as discussed in 
section III.F.3 of the proposal preamble (88 FR 22790, April 13, 2023), 
our evaluation of the performance test data shows that these controls 
can achieve greater than 99 percent emission reduction.\47\ We 
evaluated 99.9 percent reduction of ARV emissions from facilities using 
at least 30 tpy of EtO,\48\ which is feasible because it is currently 
achieved by one-third of these facilities. Of these 12 facilities that 
are currently achieving this emission reduction, nine use catalytic 
oxidizers, two use a catalytic oxidizer and gas/solid reactor in 
series, one uses a thermal oxidizer, and one uses a gas/solid reactor. 
Note that this does not sum to 12 because one facility uses two 
different types of control systems to reduce its ARV emissions.\49\ A 
99.9 percent emission reduction would eliminate ARV emissions as a 
contributor to a facility's MIR to exceed 100-in-1 million for 
facilities using at least 30 tpy of EtO.\50\
---------------------------------------------------------------------------

    \47\ While the types of controls used for ARVs are the same as 
those used for SCVs, the distribution of these controls is 
different. For example, the use of catalytic oxidizers and gas/solid 
reactors is more prominent when controlling ARV emissions, while the 
use wet scrubbers is more prominent when controlling SCV emissions. 
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.
    \48\ As discussed above, one of the facilities where allowable 
ARV emissions contribute to the facility's MIR exceeding 100-in-1 
million uses 44 tpy. Evaluating the emission reduction for 
facilities where EtO use is at least 30 tpy provides a sufficient 
buffer in case the EtO use at this facility drops to below 40 tpy.
    \49\ As part of the proposed rulemaking, a similar analysis was 
conducted for ARVs at facilities where EtO use is at least 10 tpy. 
See section III.F.3.a of the proposal preamble for more details on 
that analysis (88 FR 22790, April 13, 2023).
    \50\ As part of the proposed rulemaking, we evaluated a 99.9 
percent emission reduction standard for ARVs at facilities where EtO 
use is at least 10 tpy as part of the technology review (see section 
III.F.3 of the proposal preamble (88 FR 22790, April 13, 2023)). For 
existing sources, this option was rejected in favor of a more cost-
effective option (i.e., 99.6 percent emission reduction). However, 
we proposed a 99.9 percent emission reduction standard for new 
sources pursuant to CAA section 112(d)(6).
---------------------------------------------------------------------------

iii. Group 2 Room Air Emissions
    There are 13 facilities, all area sources, where revised allowable 
Group 2 room air emissions contribute to the facilities' MIRs exceeding 
100-in-1 million and the EtO usage at these facilities ranges from 4 
tpy to 446 tpy.\51\ Because Group 2 room air emissions contribute 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.
---------------------------------------------------------------------------

    \51\ 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 IV.B of this preamble, we are finalizing a 
GACT standard for previously unregulated Group 2 room air emissions at 
existing area source facilities. Specifically, we are finalizing under 
CAA section 112(d)(5) that area source facilities lower the EtO 
concentration within each sterilization chamber to 1 ppm before the 
chamber can be opened.\52\ Because there is still unacceptable risk 
from facilities where EtO usage is above 4 tpy, this requirement will 
ultimately apply only to existing Group 2 room air emissions at 
facilities where EtO use is less than 4 tpy.
---------------------------------------------------------------------------

    \52\ As discussed in section IV.B of this preamble, we are 
finalizing an 80 percent emission reduction standard for all new 
Group 2 room air emissions at area source facilities, regardless of 
EtO use, under CAA section 112(d)(5).
---------------------------------------------------------------------------

    In evaluating the appropriate GACT standard for previously 
unregulated existing Group 2 room air emissions at area source 
facilities, we considered an emission reduction of 80 percent that 
reflects the use of control devices (Option 1) but did not finalize 
that option under CAA section 112(d)(5) for reasons stated in section 
IV.B.3.b. However, having determined under CAA section 112(f)(2) that 
the risk for the source category is unacceptable, we are determining 
the emissions standards necessary to reduce risk to an acceptable level 
without considering costs. We evaluated 80 percent emission reduction 
of Group 2 room air emissions from area source facilities using at 
least 4 tpy but less than 20 tpy of EtO. As discussed in section 
IV.B.3.b of this preamble, 80 percent is the manufacturer guarantee for 
room air emissions controls provided by one of the commenters. We do 
not have any performance test data for Group 2 room air emissions at 
these facilities, so it is unknown whether these sources can achieve 
greater than 80 percent emission reduction. An 80 percent reduction 
would eliminate Group 2 room air emissions as a contributor to a 
facility's MIRs exceeding 100-in-1 million for area source facilities 
using at least 4 tpy but less than 20 tpy.
    For area source facilities using at least 20 tpy, further reduction 
would be needed to eliminate Group 2 room air emissions as a 
contributor to a facility's MIR exceeding 100-in-a-million. Our data do 
not identify any add-on controls beyond those we have already 
considered when finalizing the standards for the previously unregulated 
Group 2 room air emission in section IV.B. However, our evaluation of 
the performance data shows that these controls can achieve greater than 
80 percent emission reduction at area source facilities where EtO use 
is at least 20 tpy. We therefore considered a more stringent Group 2 
room air emission standard for these facilities. We evaluated 98 
percent reduction of Group 2 room air emissions from area source 
facilities using at least 20 tpy, which is the emission reduction that 
has been achieved in one-third of the

[[Page 24121]]

available performance test runs for these facilities.\53\ 98 percent 
reduction would eliminate Group 2 room air emissions as a contributor 
to a facility's MIR exceeding 100-in-a-million for area source 
facilities where EtO use is at least 20 tpy.
---------------------------------------------------------------------------

    \53\ All of these facilities use gas/solid reactors to control 
their Group 2 room air emissions.
---------------------------------------------------------------------------

iv. CEV Emissions
    There is one facility within the source category where revised 
allowable emissions from CEVs contribute to the facility's MIR 
exceeding 100-in-1 million, and this is an area source facility that 
currently uses 446 tpy of EtO. The previous subpart O did not regulate 
CEVs at area source facilities. As discussed in section IV.B of this 
preamble, we are finalizing a GACT standard for these sources. 
Specifically, pursuant to CAA section 112(d)(5), we are finalizing a 99 
percent emission reduction standard for CEVs at area source facilities.
    Our data do not identify any add-on controls beyond those we have 
already considered when finalizing the standards for CEVs in section 
IV.B. However, our evaluation of the performance test data shows that 
these controls can achieve greater than 99 percent reduction. We 
therefore considered a more stringent CEV emission standard for area 
source facilities where EtO use is at least 400 tpy. We evaluated 99.9 
percent reduction of CEV emissions from facilities where EtO use is at 
least 400 tpy, which is the emission reduction that is currently 
achieved by 75 percent of these facilities.\54\ A 99.9 percent 
reduction would eliminate CEV emissions as a contributer to a 
facility's MIR exceeding 100-in-1-million for facilities where EtO use 
is at least 400 tpy.
---------------------------------------------------------------------------

    \54\ There are three facilities that are currently achieving 
this emission reduction. Of these three facilities, two use 
catalytic oxidizers, and one uses a wet scrubber.
---------------------------------------------------------------------------

v. Group 1 Room Air Emissions
    There are four area source facilities within the source category 
where revised allowable Group 1 room air emissions contribute to the 
facilities' MIRs exceeding 100-in-1 million, and the EtO usage at these 
facilities ranges from 44 to 446 tpy. The previous subpart O did not 
regulate Group 1 room air emissions at area source facilities. As 
discussed in section IV.B of this preamble, we are finalizing a GACT 
standard for these sources. Specifically, pursuant to CAA section 
112(d)(5), we are finalizing an 80 percent emission reduction as the 
GACT standard for Group 1 room air emissions at area source facilities.
    Our data do not identify any add-on controls beyond those we have 
already considered when finalizing the standards for Group 1 room air 
emissions in section IV.B. However, our evaluation of the performance 
test data shows that these controls can achieve greater than 80 percent 
reduction. We therefore considered a more stringent Group 1 room air 
emission standard for area source facilities where EtO use is at least 
40 tpy. We evaluated 98 percent emission reduction of Group 1 room air 
emissions from area source facilities using at least 40 tpy, which is 
the emission reduction that has been achieved in all but one of the six 
available performance test runs for these facilities.\55\ A 98 percent 
reduction would eliminate Group 1 room air emissions as a contributor 
to a facility's MIRs exceeding 100-in-1-million for area source 
facilities where EtO use is at least 40 tpy.
---------------------------------------------------------------------------

    \55\ All of these facilities use gas/solid reactors to control 
their Group 1 room air emissions.
---------------------------------------------------------------------------

    Considering all of the emission reductions that we evaluated above, 
the source category MIR would be reduced to 100-in-1 million. This 
means that all facilities would have an MIR at or below 100-in-1 
million,\56\ and the population exposed to risk levels greater 100-in-1 
million would be reduced to zero. In addition, the population exposed 
to risk levels greater than or equal to 1-in-1 million living within 50 
km of a facility would be reduced to between 710,000 (when considering 
some facilities are currently performing better than the standards) and 
1.41 million people (when considering all facilities perform at the 
level of the standards). Finally, the cancer incidence would be reduced 
from 0.9 to between 0.1 (when considering some facilities are currently 
performing better than the standards) and 0.2 (when considering all 
facilities perform at the level of the standards), or from 1 cancer 
case every 1.1 years to 1 cancer case every 5 to 10 years. For these 
reasons, we find that the preceding emission reductions that we 
evaluated reduce risks to an acceptable level. These emission reduction 
measures are:
---------------------------------------------------------------------------

    \56\ Considering actual emissions, most facilities (i.e., 87 out 
of 88) would have an MIR less than 100-in-1 million.
---------------------------------------------------------------------------

     99.99 percent emission reduction for SCVs at facilities 
where EtO use is at least 30 tpy,
     99.9 percent emission reduction for SCVs at facilities 
where EtO use is at least 10 tpy but less than 30 tpy,
     99.8 percent emission reduction for SCVs at facilities 
where EtO use is at least 1 tpy but less than 10 tpy,
     99.9 percent emission reduction for ARVs at facilities 
where EtO use is at least 30 tpy,
     99.9 percent emission reduction for CEVs at facilities 
where EtO use is at least 400 tpy,
     98 percent emission reduction for Group 1 room air 
emissions at area source facilities where EtO use is at least 40 tpy,
     98 percent emission reduction for Group 2 room air 
emissions at area source facilities where EtO use is at least 20 tpy, 
and
     80 percent emission reduction for Group 2 room air 
emissions at area source facilities where EtO use is at least 4 tpy but 
less than 20 tpy.
b. Ample Margin of Safety (Step 2)
    At step 1 of our review of residual risks under CAA section 
112(f)(2), we have identified a suite of standards and determined that 
they are necessary to reduce risks to an acceptable level. These 
include standards for SCVs at facilities with EtO usage of at least 1 
tpy, ARVs at facilities with EtO usage of at least 30 tpy, CEVs at area 
source facilities with EtO usage of at least 400 tpy, Group 1 room air 
emissions at area source 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 four tpy. For step 2 of our review of residual risks, we 
evaluate whether more stringent standards are necessary to provide an 
ample margin of safety to protect public health. While we do not 
consider costs in the step 1 analysis, costs are a factor we consider 
in the step 2 analysis. For details on the assumptions and 
methodologies used in the costs and impacts analyses, see the technical 
memorandum titled Ample Margin of Safety Analysis for Ethylene Oxide 
Commercial Sterilization--Promulgation Rule Review for the Ethylene 
Oxide Commercial Sterilization Source Category, which is available in 
the docket for this rulemaking.
    As part of the proposed rulemaking, we considered six options 
(which are identified in the proposal preamble table 22 (88 FR 22829) 
and proposed Control Options A and C as part of the ample margin of 
safety analysis. Control Option A would have required 99.94 percent 
emission reduction for SCVs at facilities where EtO use is at least 10 
tpy but less than 40 tpy. We are not finalizing Control Option A for 
the following reasons. First, this option is less stringent than the 
standard we have

[[Page 24122]]

already identified in Step 1 (99.99 percent emission reduction) for SCV 
emissions at facilities where EtO use is at least 30 tpy.\57\ Second, 
for facilities where EtO use is less than 30 tpy, we do not have any 
performance tests showing that these facilities can perform better than 
the manufacturer guarantee (i.e., 99.9 percent emission reduction for 
SCVs). For these reasons, we are not finalizing Control Option A as 
part of this rulemaking. Control Option C would have required 99.8 
percent emission reduction for SCVs at facilities where EtO use is at 
least 1 tpy but less than 10 tpy. As discussed in section IV.C.2.a of 
this preamble (step 1 of risk review), Control Option C is one of the 
standards identified under the revised Step 1 analysis as necessary to 
reduce risks to an acceptable level.
---------------------------------------------------------------------------

    \57\ For facilities where use is less than 30 tpy, we do not 
have performance test data indicating that 99.99 percent emission 
reduction for SCVs is technical feasible.
---------------------------------------------------------------------------

    In addition, we evaluated the following options but rejected them 
for the reasons discussed below:
    [cir] For ARVs at facilities where EtO use is at least 30 tpy, we 
do not have data showing that it is technically feasible for all 
facilities to achieve greater than 99.9 percent emission reduction 
(which is the standard applicable to these sources that we have 
determined under step 1 as necessary to reduce risks to an acceptable 
level).
     For ARVs at facilities where EtO use is less than 10 tpy, 
we were unable to identify any cost-effective options that achieve 
emission reduction greater than the current 99 percent emission 
reduction standard (GACT). More information is presented in the 
technical memorandum titled Ample Margin of Safety Analysis for 
Ethylene Oxide Commercial Sterilization--Promulgation Rule Review for 
the Ethylene Oxide Commercial Sterilization Source Category, which is 
available in the docket for this rulemaking.
     For Group 2 room air emissions at area source facilities 
where EtO use is at least 20 tpy, we do not have data indicating that 
it is technically feasible for all facilities to achieve greater than 
98 percent emission reduction (which is the standard applicable to 
these sources that we have determined under step 1 as necessary to 
reduce risks to an acceptable level).
     For Group 2 room air emissions at area source facilities 
where EtO use is less than 20 tpy, we do not have any performance tests 
showing that these facilities can perform better than the manufacturer 
guarantee (i.e., 80 percent emission reduction for room air emissions, 
which is the standard for facilities using at least 4 tpy but less than 
20 tpy of EtO that we have determined under step 1 as necessary to 
reduce risks to an acceptable level).
     For Group 2 room air emissions at area source facilities 
where EtO use is less than 4 tpy, 80 percent emission reduction is not 
cost effective.\58\
---------------------------------------------------------------------------

    \58\ As discussed in section IV.B.3.b of this preamble, we 
analyzed this option as part of the GACT analysis and found it to be 
cost-effective. However, this analysis included all facilities in 
the source category (i.e., not just those where EtO use is less than 
4 tpy).
---------------------------------------------------------------------------

     For Group 1 room air emissions at area source facilities 
where EtO use is at least 40 tpy, we do not have data indicating that 
it is technically feasible for all facilities to achieve greater than 
98 percent emission reduction (which is the standard for these affected 
sources that we have identified in Step 1 as necessary to reduce risks 
to an acceptable level).
     For Group 1 room air emissions at area source facilities 
where EtO use is less than 40 tpy, we do not have any performance tests 
showing that these facilities can perform better than the manufacturer 
guarantee (i.e., 80 percent emission reduction for room air emissions, 
which we have established in this final rule as the GACT standard for 
Group 1 room air emissions at these facilities).
    However, there are two potential options. One potential option is 
99.6 percent emission reduction for ARVs at facilities where EtO use is 
at least 10 tpy but less than 30 tpy. This is cost effective and is 
already being achieved by these facilities. The other potential option 
is to further reduce CEV emissions at area source facilities.\59\ Under 
this option, which would reduce CEV emissions by 99.9 percent at area 
source facilities where EtO use is at least 60 tpy less than 400 
tpy,\60\ costs were found to be a $6,820,000 total capital investment 
and a $1,670,000 total annualized cost. The estimated EtO emissions 
reductions are 1.9 tpy (i.e., 3,720 lb/year) with a cost effectiveness 
of $895,000 per ton of EtO (i.e., $448 per lb of EtO). Considering EtO 
is a highly potent carcinogen, the cost-effectiveness number of this 
option is within the range of the values that we have determined to be 
cost-effective for highly toxic HAPs. As explained in section IV.B.3.b 
of this preamble, 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 we do not know what the full extent of risk 
reductions would be, we estimate that, compared to the measures in step 
1, this control option would further reduce the population exposed to 
risk levels greater than or equal to 1-in-1 million by additional 
10,000-30,000 people. For area sources where EtO use is less than 60 
tpy, we do not have any performance test data showing that existing 
controls can achieve greater than 99 percent reduction for CEVs (which 
is the GACT standard we have established in this final rule for CEV at 
area sources). In addition, for area source facilities where EtO use is 
at least 400 tpy, we were unable to identify any cost-effective 
options. Therefore, we did not consider a more stringent CEV standard 
for facilities where EtO use at least 400 tpy.
---------------------------------------------------------------------------

    \59\ As discussed in section IV.B.3.b of this preamble, pursuant 
to CAA sections 112(d)(2) and 112(d)(3), we are finalizing a 99.94 
percent emission reduction standard for CEVs at major source 
facilities. We did not identify any cost-effective BTF options.
    \60\ As discussed in step 1 analysis, pursuant to CAA section 
112(f)(2), this standard for CEVs at area source facilities where 
EtO usage is at least 400 tpy is necessary to reduce risks to an 
acceptable level.
---------------------------------------------------------------------------

    In the post control scenario (i.e., with the implementation of the 
standards identified under step 1 and the two potential options 
discussed immediately above in this step 2 analysis, we estimated that 
the baseline cancer MIR of 6,000-in-1 million for actual emissions and 
8,000-in-1 million for allowable emissions would be reduced to 100-in-1 
million, with EtO driving the risk. While the MIR for the source 
category will be 100-in-1 million, we estimate that most facilities 
(i.e., 87 out of 88) will have an MIR less than 100-in-1 million. There 
is an estimated reduction in cancer incidence to 0.2 excess cancer 
cases per year (or one excess case every 5 years), down from 0.9 excess 
cancer cases per year (or one excess cancer case every 1.1 years) for 
baseline actual emissions and down from 8 excess cancer cases per year 
(or one excess cancer case every 1.5 months) for baseline allowable 
emissions. We estimate that, after full implementation of this final 
rule, 0 people would have cancer risks greater than 100-in-1 million, 
down from 19,000 people for actual emissions and 260,000 people for 
allowable emissions. In addition, the number of people estimated to 
have a cancer risk greater than or equal to 1-in-1 million would be 
reduced to 1.38 million people, down from 8.5 million people for actual 
emissions and 62 million people for

[[Page 24123]]

allowable emissions (table 19 of this preamble).
    Again, we note that some facilities are currently performing better 
than the controls finalized under CAA sections 112(f)(2), and in that 
case we estimate the maximum lifetime individual cancer risk as 100-in-
1 million, with EtO driving the risk. The total estimated cancer 
incidence is estimated to be 0.1 excess cancer cases per year, or 1 
excess case in every 10 years, with approximately 700,000 people 
estimated to have cancer risks greater than or equal to 1-in-1 million 
and 0 people estimated to have cancer risks greater than 100-in-1 
million (table 19 of this preamble).

  Table 19--Baseline and Post-Control Risk (After Controls Promulgated Under CAA Sections 112(F)(2) Summary For
          the Commercial Sterilization Facilities Source Category Based on Emissions in the Final Rule
----------------------------------------------------------------------------------------------------------------
                                     Inhalation cancer risk                   Population cancer risk
                               ---------------------------------------------------------------------------------
                                    Maximum                           Cancer
                                  individual                         incidence       >100-in-1     [gteqt]1-in-1
                                  risk (in 1       Risk driver      (cases per        million         million
                                   million)                            year)
----------------------------------------------------------------------------------------------------------------
Actual Emissions Baseline Risk           6,000  ethylene oxide..             0.9          19,000       8,500,000
Allowable Emissions Baseline             8,000  ethylene oxide..               8         260,000      62,000,000
 Risk.
Post-control Risk.............             100  ethylene oxide..     \1\ 0.1-0.2               0    \1\ 700,000-
                                                                                                       1,380,000
----------------------------------------------------------------------------------------------------------------
\1\ Ranges in values account for if all facilities were performing at the level of the standards (high end) to
  considering facilities that are currently performing better than the standards (low end).

    Additional details of the analyzed risks can be found in the 
Residual Risk Assessment for the Commercial Sterilization Facilities 
Source Category in Support of the 2024 Risk and Technology Review Final 
Rule, available in the docket for this rulemaking.
    Based on our ample margin of safety analysis, including all health 
information and the associated cost and feasibility discussed above, we 
find that requiring the standards that, based on our analysis, would 
bring risks to an acceptable level, along with 99.6 percent emission 
reduction for ARVs at facilities where EtO use is at least 10 tpy but 
less than 30 tpy and 99.9 percent emission reduction for CEVs at area 
source facilities where EtO use is at least 60 tpy but less than 400 
tpy, would provide an ample margin of safety to protect public health.
c. Environmental Effects
    As explained in our proposed rule, 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. For the reason stated above, 
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.
d. Rule Changes
    Based on comments received on the proposed rulemaking, we are 
finalizing the following emissions standards pursuant to CAA section 
112(f)(2):
     99.99 percent emission reduction for SCVs at facilities 
where EtO use is at least 30 tpy,
     99.9 percent emission reduction for SCVs at facilities 
where EtO use is at least 10 tpy but less than 30 tpy,
     99.8 percent emission reduction for SCVs at facilities 
where EtO use is at least 1 tpy but less than 10 tpy,
     99.9 percent emission reduction for ARVs at facilities 
where EtO use is at least 30 tpy,
     99.6 percent emission reduction for ARVs at facilities 
where EtO use is at least 10 tpy but less than 30 tpy,
     99.9 percent emission reduction for CEVs at area source 
facilities where EtO use is at least 60 tpy,
     98 percent emission reduction for Group 1 room air 
emissions at area source facilities where EtO use is at least 40 tpy,
     98 percent emission reduction for Group 2 room air 
emissions at area source facilities where EtO use is at least 20 tpy, 
and
     80 percent emission reduction for Group 2 room air 
emissions at area source facilities where EtO use is at least 4 tpy but 
less than 20 tpy.
    We are not finalizing the work practice standards that were 
proposed for facilities where the MIR remained greater than 100-in-1 
million after the imposition of requirements under ``Control Option 
1'', which would have required facilities to limit their existing Group 
2 room air emissions to a maximum volumetric flow rate of 2,900 dscfm 
and a maximum EtO concentration of 30 ppbv. We had proposed these 
standards based on the risk review we conducted during the proposal 
stage, which has been substantially revised. As discussed above, based 
on the revised risk review, we are finalizing a different suite of 
standards pursuant to CAA section 112(f)(2) to reduce risks to an 
acceptable level and provide an ample margin of safety to protect 
public health.
3. What key comments did we receive on the risk review, and what are 
our responses?
    This section provides comment summaries and responses for the key 
comments received regarding our exclusion of allowable emissions from 
the risk assessment, the control requirements proposed for SCVs, and 
the work practice standards that were proposed for facilities where the 
MIR remained greater than 100-in-1 million after the imposition of 
requirements under ``Control Option 1'' evaluated in the residual risk 
assessment during the proposal stage, as well as the proposed GACT 
standards that were incorporated into the residual risk assessment. We 
received comments against the exclusion of allowable emissions from the 
risk assessment, the control requirements proposed for SCVs, and the 
work practice standards that were proposed for facilities where the MIR 
remained greater than 100-in-1 million after the imposition of 
requirements under ``Control Option 1.'' Other comments on these 
issues, as well as on additional issues regarding the residual risk 
review and our proposed changes based on the residual risk review, can 
be found in the document, Summary of Public Comments and Responses for 
the Risk and Technology Review for

[[Page 24124]]

Commercial Sterilization Facilities, available in the docket for this 
rulemaking.
    Comment: Two commenters contended that we should use allowable 
emissions when conducting residual risk assessments. One commenter 
stated that actual emissions only provide a snapshot in time and that 
there is no legal requirement at the Federal level to maintain 
emissions beyond the NESHAP requirements in any given year. The 
commenter also referenced a 2010 Science Advisory Board (SAB) report 
that recommended we use ``facility-specific allowable emissions 
reflecting current regulatory limits.'' \61\
---------------------------------------------------------------------------

    \61\ Commenter provided the following reference: EPA Science 
Advisory Board, Review of EPA's draft entitled, ``Risk and 
Technology Review (RTR) Risk Assessment Methodologies: For Review by 
the EPA's Science Advisory Board with Case Studies--MACT I Petroleum 
Refining Sources and Portland Cement Manufacturing'', at ii, (May 7, 
2010), https://www.regulations.gov/document/EPA-HQ-OAR-2010-0682-0103.
---------------------------------------------------------------------------

    Response: We agree with commenters that allowable emissions should 
be considered as part of the residual risk assessment. As discussed in 
section III.C of the proposed rulemaking (88 FR 22790), because 
allowable emissions and risks were higher than actual emissions, and in 
light of our finding that risks were unacceptable based on actual 
emissions, we determined that a separate assessment of allowable 
emissions was unnecessary. However, for the reasons stated by the 
commenters, we have incorporated allowable emissions into our revised 
risk assessment as part of this final rulemaking.
    Comment: Two commenters expressed the following concerns with the 
99.94 percent emission reduction standard for SCVs:
     Our technical publications on reduction ranges for add-on 
control equipment for HAPs do not show that a destruction and removal 
efficiency of 99.94 percent is achievable under normal continuous 
operation.
     The proposed requirement does not require additional 
controls based on new technology, but requires achieving greater 
efficiency from existing controls. Specifically, one commenter stated 
that nothing in the proposal preamble suggests that the control systems 
installed in order to meet the current SCV standard need to be replaced 
or their performance upgraded. The commenter further stated that our 
cost estimates include nothing with respect to controls for SCVs.
     Emission control device manufacturers do not guarantee a 
destruction removal efficiency of 99.94 percent for SCVs.
    Two commenters stated that emissions standards should be based on 
achievable, manufacturer guaranteed destruction removal efficiency of 
emission control equipment. One commenter stated that, based on their 
discussions with control device manufacturers, they believe that the 
best and most advanced technologies will be guaranteed to meet a 99.9 
percent emission reduction standard for SCVs.
    Response: We disagree with the commenters that our technical 
publications on reduction ranges for add-on control equipment for HAPs 
do not show that an emission reduction of 99.94 percent (and, 
therefore, any greater emission reduction) is achievable under normal 
continuous operation for SCVs. Such a performance test was conducted 
for at least two systems that control SCV emissions, and the reported 
emission reduction for both of these systems was 99.99 percent. Below 
is a discussion on the relevant points for each performance test:
     The first performance test was conducted on November 17, 
1999.\62\ It is unknown what the EtO use at this facility was at the 
time of the performance test, but it is expected that it was somewhere 
between 10 tpy and 30 tpy. At the time of the performance test, the 
facility used a wet scrubber to control its SCV emissions.\63\ Prior to 
November 2, 2001, we required facilities to test the both the first and 
last evacuations of the SCV. The SCV concentration decreases over time, 
so any emission reductions between the first and last evacuations are 
going to be at least as high as that of the last evacuation. For this 
performance test, the average emission reduction at the first 
evacuation was 99.9946 percent, and the average emission reduction at 
the last evacuation was 99.99 percent. This means that the emission 
reduction over all the SCV cycles exceeded 99.99 percent. While this 
performance test data is almost 25 years old, emission control 
technology has continued to improve over time, and emission reductions 
today are likely higher.
---------------------------------------------------------------------------

    \62\ https://www.regulations.gov/document/EPA-HQ-OAR-2019-0178-0297.
    \63\ This facility continues to use a wet scrubber to control 
its SCV emissions to this day.
---------------------------------------------------------------------------

     The data from this performance test indicates that, for 
facilities where EtO use is at least 30 tpy, any SCV control system 
that is achieving higher than 99.9946 percent emission reduction on the 
first evacuation is likely achieving at least 99.99 percent emission 
reduction overall. Our current performance test data indicates that at 
least 15 facilities where EtO use is at least 30 tpy are currently 
achieving greater than 99.9946 percent emission reduction on the first 
evacuation, and the highest emission reduction on the first evacuation 
that we have observed is 99.99999982 percent. Of these 15 facilities 
that are currently achieving this emission reduction, eight use wet 
scrubbers, three use a wet scrubber and gas/solid reactor in series, 
two use thermal oxidizers, one uses a catalytic oxidizer, and one uses 
a wet scrubber and catalytic oxidizer in series.
     The second performance test was conducted on March 10, 11, 
and 12, 2020,\64\ and EtO use at this facility is 229.2 tpy. This 
facility uses wet scrubbers and gas/solid reactors in series to control 
its SCV emissions. Due to the configuration of the control system at 
this facility, there is no mechanism to test the SCVs on their own. 
Therefore, this performance test was conducted for all emission sources 
at the facility. For lower concentration streams like ARVs, CEVs, and 
room air emissions, emission reductions tend to be lower. Therefore, it 
is likely that the SCV emission reduction at this facility exceeds 
99.99 percent.
---------------------------------------------------------------------------

    \64\ https://www.regulations.gov/document/EPA-HQ-OAR-2019-0178-0349.
---------------------------------------------------------------------------

    As a general matter, it is not our policy to simply rely on 
manufacturer guarantees when setting or revising emission standards. 
Typically, we evaluate performance tests to see what the controls are 
actually achieving in practice and then set or revise the standards 
based on that evaluation. However, if representative performance test 
data are not available, then manufacturer guarantees may be considered. 
We also note that it is common within this industry to combine 
different types of control devices in series when reducing emissions. 
Since these control devices are often made by different manufacturers, 
there is no manufacturer guarantee available for these systems. We do 
not share the commenters' concerns that emission control device 
manufacturers do not guarantee a destruction removal efficiency of 
99.94 percent for SCVs, as representative performance test data is 
available and indicates that these emission reductions (and, in fact, 
higher emission reductions) are achievable for higher use facilities. 
However, such performance test data are not available for smaller 
users, and it is not known whether those facilities can meet the 
emission reduction that the higher use facility is demonstrating. 
Therefore, we agree with commenters that consideration of manufacturer 
guarantees is warranted for lower use facilities, and the

[[Page 24125]]

standards that we are finalizing for SCVs at facilities where EtO use 
is less than 30 tpy do not exceed the manufacturer guarantee.
    In addition, we disagree with one commenter's assertion that there 
is nothing in the proposal preamble to suggest that the control systems 
installed in order to meet the current SCV standard need to be replaced 
or their performance upgraded. Furthermore, the commenter's assertion 
that our cost estimates include nothing with respect to controls for 
SCVs is incorrect. As discussed in section II.A of this preamble, under 
the first step of the residual risk assessment, if risks are 
unacceptable, the EPA must determine the emissions standards necessary 
to reduce risk to an acceptable level without considering costs. While 
we did not conduct a cost analysis for the SCV standards that we are 
finalizing pursuant to CAA section 112(f)(2) step 1 (risk acceptability 
analysis), we assume that new controls would be needed in order to 
achieve those standards, and the cost of those controls are included in 
the total costs of the rule. However, we note that the final standard 
is simply an emission reduction standard, and owners and operators may 
choose to meet the standard however they see fit (e.g., either through 
process changes, the replacement of a control system, or the use of 
additional control devices to further reduce emissions from an existing 
control system). In some cases, existing controls may already be 
achieving the standard, and in that case, no changes are required.
    Comment: Several commenters stated that reducing the volumetric 
flow rate from Group 2 room air emissions to 2,900 dscfm would be 
detrimental to sterilization operations and may make it impossible to 
achieve the proposed PTE requirement.
    Response: Based on comments received on the proposed rulemaking, we 
revised the risk assessment, which resulted in different emission 
reduction measures than what we proposed to bring the risk to the 
acceptable level. The proposed work practice standards are no longer 
necessary to bring the MIR of Group 2 room air emissions at area source 
facilities to 100-in-1 million. Therefore, we are not including a work 
practice standard that would require any facilities to reduce their 
throughput as part of this final rule.
4. What is the rationale for our final approach and final decisions for 
the risk review?
    As noted in our proposal, we set 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 benchmark on MIR of approximately 1-in-10 
thousand'' (88 FR 22790, April 13, 2023; see also 54 FR 38045, 
September 9, 1989). We weigh all health risk factors in our risk 
acceptability determination, including the cancer MIR, cancer 
incidence, the maximum TOSHI, the maximum acute HQ, the extent and the 
distribution of cancer and noncancer risks in the exposed population, 
multipathway risks, and the risk estimation uncertainties. 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.
    Since proposal, our determinations regarding risk acceptability, 
ample margin of safety, or adverse environmental effects have not 
changed. The revised risk assessment (see document, Residual Risk 
Assessment for the Commercial Sterilization Facilities Source Category 
in Support of the 2024 Risk and Technology Review Final Rule, which is 
available in the docket for this rulemaking) shows that, after 
application of controls finalized in this rulemaking, the MIR for the 
source category is 100-in-1 million. Therefore, after application of 
the controls for SCVs at facilities where EtO use is at least 1 tpy, 
ARVs at facilities where EtO use is at least 30 tpy, CEVs at area 
source facilities where EtO use is at least 400 tpy, Group 1 room air 
emissions at area source facilities where EtO use is at least 40 tpy, 
and Group 2 room air emissions at area source facilities where EtO use 
is at least four tpy, we find that the risks are acceptable and that 
the final standards will achieve an ample margin of safety to protect 
public health.

D. Technology Review for the Commercial Sterilization Facilities Source 
Category

1. What did we propose pursuant to CAA section 112(d)(6) for the 
Commercial Sterilization Facilities source category?
    Based on our technology review for the Commercial Sterilization 
Facilities source category, we proposed under CAA section 112(d)(6) 
changes to the standards for SCVs where EtO use is at least 10 tpy, 
SCVs where EtO use is at least 1 tpy but less than 10 tpy, and ARVs 
where EtO use is at least 10 tpy. We provide a summary of our findings, 
as proposed, in this section. In general, while the types of controls 
have essentially remained the same since promulgation of subpart O, 
available information show greater emission reduction since then for 
some of these control options.
    For SCVs, we proposed the following emission standards pursuant to 
CAA section 112(d)(6):
     99.94 percent reduction for new and existing SCVs at 
facilities where EtO use is at least 10 tpy, and
     99.8 percent reduction for new and existing SCVs at 
facilities where EtO use is at least 1 tpy but less than 10 tpy.
    These are the maximum SCV emission reductions with which compliance 
can be demonstrated. We evaluated these standards against the maximum 
SCV emission reductions that all facilities are currently meeting 
within each subcategory. For more information, see sections III.F.1 and 
III.F.2 of the proposal preamble (88 FR 22790, April 13, 2023).
    For ARVs, we proposed the following emission standards pursuant to 
CAA section 112(d)(6):
     99.6 percent emission reduction for existing ARVs at 
facilities where EtO use is at least 10 tpy, and
     99.9 percent emission reduction for new ARVs at facilities 
where EtO use is at least 10 tpy.
    These are the emission reductions that have been demonstrated by 75 
percent and 50 percent of all available performance tests, 
respectively. We evaluated both emission reductions for new and 
existing ARVs. For more information, see section III.F.3 of the 
proposal preamble (88 FR 22790, April 13, 2023).
2. How did the technology review change for the Commercial 
Sterilization Facilities source category?
    We are finalizing the following emission standards as a result of 
the

[[Page 24126]]

technology review for the Commercial Sterilization Facilities source 
category, as proposed:
     99.8 percent emission reduction for new and existing SCVs 
at facilities where EtO use is at least 1 tpy but less than 10 tpy,
     99.6 percent emission reduction for existing ARVs at 
facilities where EtO use is at least 10 tpy, and
     99.9 percent emission reduction for new ARVs at facilities 
where EtO use is at least 10 tpy.
    For new and existing SCVs at facilities where EtO use is at least 
10 tpy, based on comments received on the proposal, we are finalizing a 
99.9 percent emission reduction, which is the manufacturer guarantee. 
There is a lack of representative performance test data for these SCVs, 
and we are unable to determine whether all facilities can achieve an 
emission reduction higher than the manufacturer guarantee. For more 
information, see section IV.D.3.a of this preamble.
3. What key comments did we receive on the technology review, and what 
are our responses?
    This section provides comment and responses for the major comments 
on our proposed CAA section 112(d)(6) standards. Other comment 
summaries and our responses for additional issues raised regarding 
these activities, as well as issues raised regarding our proposed 
revisions, can be found in the document Summary of Public Comments and 
Responses for the Risk and Technology Review for Commercial 
Sterilization Facilities, available in the docket for this rulemaking.
a. SCVs at Facilities Where EtO Use Is at Least 10 tpy
    Comment: Several commenters questioned whether the proposed 
emission standards for SCVs at facilities where EtO use is at least 10 
tpy could be achieved with existing technology and stated that we 
should consider manufacturer guarantees when revising the standard, 
along with a maximum concentration limit. The commenters stated that we 
arrived at a 99.94 percent emission reduction standard based on 
performance tests that used the previous testing procedures in Subpart 
O. These consisted of one-hour test runs that occurred during the 
initial vacuum event, when EtO loading to the control system (and, 
therefore, emission reduction) is high. The commenters further stated 
that we proposed extending the duration of each test run to 24 hours, 
which would cover a variety of operating conditions, including periods 
of low inlet concentration, which have not been required to be tested. 
The commenters contended that the performance test results based on the 
proposed testing procedures would be lower than those under the 
previous testing procedures. One commenter stated that there are no 
data confirming whether state-of-the-art control systems can meet a 
99.94 percent emission reduction standard for SCVs where each 
performance test run is 24 hours, and another commenter stated that we 
must ensure that any required emission reduction standards that are 
finalized for SCVs are proven and achievable as part of performance 
tests consisting of 24-hour test runs. One commenter stated that, based 
on their discussions with control device manufacturers, they believe 
that the best and most advanced technologies will be guaranteed to meet 
a 99.9 percent emission reduction standard for SCVs.
    Response: We agree with the commenters that it is not appropriate 
to use performance test data based on the previous testing procedures 
in Subpart O to justify revisions to the emission standards for SCVs. 
We disagree with one commenter's statement that there are no data 
confirming whether state-of-the-art control systems can meet a 99.94 
percent emission reduction standard for SCVs where each test run is 24 
hours. As discussed in section IV.C.3, such data exist for at least one 
system that controls SCV emissions. However, the EtO usage at this 
facility is fairly high, and we are unable to determine whether smaller 
users can meet this emission standard. With respect to the suggestion 
by some commenters that we consider a manufacturer guarantee reduction 
level, which one commenter stated is 99.9 percent emission reduction 
for SCVs, we have no data disputing such level or reason to question 
the manufacturer's guarantee. Further, as discussed in our response to 
the next comment below, we find the cost of this option to be 
reasonable. Therefore, pursuant to CAA section 112(d)(6), we are 
finalizing a 99.9 percent emission reduction standard for SCVs at 
facilities where EtO use is at least 10 tpy.\65\
---------------------------------------------------------------------------

    \65\ We also note that, as discussed in section IV.F.3 of this 
preamble, we are finalizing a requirement for owners and operators 
to include a representative performance test period for SCVs, along 
with a justification, in their stack test protocol, so that the 
delegated authorities can review and approve or deny the protocol as 
appropriate. This will ensure that performance tests provide a more 
accurate representation of SCVs emission reductions.
---------------------------------------------------------------------------

    We disagree with the commenter's suggestion that we should consider 
a maximum concentration limit along with the percentage reduction 
standard. As discussed in section IV.B.3.a, we are concerned that some 
owners and operators may dilute the air flow of the emissions stream to 
meet a concentration standard, which would not result in any actual 
emission reductions. Furthermore, it is not appropriate to establish 
upper-bound limitations on air flow within this source category, as 
additional flow may be necessary in order to mitigate any potential 
safety issues that may arise. Therefore, we are not finalizing any 
concentration standards as part of this rulemaking.
    Comment: One commenter stated that, for the SCV technology rule 
under CAA section 112(d)(6), we merely referred back to, and repeated 
the proposed standards of, the residual risk review. The commenter 
further stated that we did not conduct the technology review as a 
separate analysis, but rather, it was inseparably intertwined with the 
residual risk review. Finally, the commenter stated there is no true 
technology review in the record and that cost considerations of the 
proposed CAA section 112(d)(6) emissions standard for existing SCVs at 
facilities where EtO use is at least 40 tpy were never considered, even 
though section 112(d)(6) requires considerations of cost.\66\
---------------------------------------------------------------------------

    \66\ In support of its comment that control costs must be 
considered under section 112(d)(6) review, the commenter cited to 
Nat'l Ass'n for Surface Finishing, 795 F.3d at 5 (``in the 
technology review, EPA periodically assess, no less often than every 
eight years, whether standards should be tightened in view of 
developments in technologies and practices since the standard's 
promulgation or last revision, and, in particular, the cost and 
feasibility of developments and corresponding emissions savings'').
---------------------------------------------------------------------------

    Response: We disagree with the commenter's statement that a 
``true'' technology review was never conducted. In the proposal 
preamble (88 FR 22839-41), the EPA discussed control options that can 
achieve further emission reductions compared to the existing subpart O 
standards. While the types of controls have essentially remained the 
same, available information shows improvement in emission reduction 
potential for some of these control options, which we consider to be a 
development in control technologies; we analyzed this development and 
proposed revisions to the standards pursuant to CAA section 112(d)(6). 
The commenter appears to take issue with the fact that these are the 
same options as those we evaluated under CAA section 112(f)(2), 
specifically under step 2 (ample margin of safety) analysis. However, 
in evaluating whether we can achieve further emission reduction and 
thus lower risks, we naturally would

[[Page 24127]]

consider controls that reflect the current developments in processes 
and technology by this industry (i.e., well performing air pollution 
control), which we are also required to evaluate under CAA section 
112(d)(6). For the reason stated above, we find the comment that our 
technology review was not a ``true'' review to be without merit.
    We acknowledge that in proposing a 99.94 percent standard pursuant 
to CAA section 112(d)(6) for SCV at facilities using at least 10 tpy 
EtO, we inadvertently evaluated the control costs for facilities using 
between 10 to 40 tpy only. However, as discussed in our comment 
response above, we no longer consider the proposed 99.94 percent 
emission reduction standard to be appropriate. As suggested by several 
commenters, we evaluated a manufacturer guarantee. Based on one 
commenter's discussions with control device manufacturers, the best and 
most advanced technologies will be guaranteed to meet 99.9 percent 
emission reduction for SCVs. The impacts of this option and the 99.6 
percent reduction option that we considered during the proposal stage 
are presented below in table 20 for existing sources:

  Table 20--Nationwide Emissions Reduction and Cost Impacts of Options Considered Under CAA Section 112(d)(6) for Existing SCVs at Facilities Where EtO
                                                                 Use Is at Least 10 Tpy
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                       Total capital   Total annual    EtO emission reductions   Cost effectiveness ($/
                Option                       Standard evaluated       investment ($)   costs ($/yr)             (tpy)                   ton EtO)
--------------------------------------------------------------------------------------------------------------------------------------------------------
1....................................  99.9 percent emission              $1,840,000        $752,000  1.14 [2,280 lb].........  $661,000 [$330/lb].
                                        reduction.
2....................................  99.6 percent emission                       0               0  0.......................  N/A.
                                        reduction.
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Based on the estimates above, and considering EtO is a highly 
potent carcinogen, the cost-effectiveness number of this option is 
within the range of the values that we have determined to be cost-
effective for highly toxic HAPs. As explained in section IV.B.3.b of 
this preamble, 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). As part of the proposed rulemaking, the highest cost-
effectiveness number that we found was $19,420,188/ton. We did not 
receive adverse comment on our finding that this is cost-effective. 
While Option 2 would prevent backsliding, it does not achieve 
additional emission reduction. Therefore, pursuant to CAA section 
112(d)(6), we are revising the standard to require facilities where EtO 
use is at least 10 tpy to reduce their emissions from existing SCVs by 
99.9 percent.
    The impacts of these options for new sources, which are presented 
in table 21 of this preamble, are based on a model plant for new SCVs 
at a facility using at least 10 tpy of EtO with the following 
assumptions reflecting the average of each of the parameters at 
existing facilities using at least 10 tpy of EtO:
     Annual EtO use: 120 tpy.
     Annual operating hours: 8,000.
     Portion of EtO going to SCVs: 94.41 percent.
     SCV flow rate: 200 cfs.

 Table 21--Nationwide Emissions Reduction and Cost Impacts of Options Considered Under CAA Section 112(d)(6) for New SCVs at Facilities Where EtO Use Is
                                                                     at Least 10 Tpy
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                       Total capital   Total annual    EtO emission reductions   Cost effectiveness ($/
                Option                       Standard evaluated       investment ($)   costs ($/yr)             (tpy)                   ton EtO)
--------------------------------------------------------------------------------------------------------------------------------------------------------
1....................................  99.9 percent emission                $523,000        $136,000  1.02 [2,040 lb].........  $134,000 [$67/lb].
                                        reduction.
2....................................  99.6 percent emission                 348,000         106,000  0.68 [1,360 lb].........  158,000 [$79/lb].
                                        reduction.
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Based on the estimates above, we find both options to be cost 
effective. Option 1 would achieve greater emission reductions than 
Option 2, and Option 1 would be more cost-effective. Therefore, 
pursuant to CAA section 112(d)(6), we are revising the standard to 
require facilities where EtO use is at least 10 tpy to reduce their 
emissions from new SCVs by 99.9 percent.
    Comment: In response to the EPA's solicitation of comment on 
whether to include a mass emission rate standard as an alternative to 
the percent emission reduction standard, two commenters were opposed to 
such an alternative. One commenter stated that mass emission rate 
standards for individual vents do not account for variability between 
facilities or variability within facilities. The commenter also stated 
that any standard that fails to reflect individual facility dynamics 
that materially affect the ability to comply is inappropriate and not 
achievable.
    Response: We agree with the commenters' concerns regarding the 
alternative, equivalent mass rate emission standards. Therefore, they 
are not included in this final rule.
b. SCVs at Facilities Where EtO Use Is at Least 1 Tpy but Less Than 10 
Tpy
    Comment: One commenter stated that they support emission reduction 
standards based on manufacturer guarantees for control equipment, along 
with a maximum concentration limit, to ensure that compliance can be 
achieved and demonstrated. In addition, the commenter did not agree 
with our method to calculate alternative, equivalent mass rate emission 
standards. Another commenter stated that, based on their discussions 
with control device manufacturers, they believe that the best and most 
advanced technologies will be guaranteed to meet a 99.9 percent 
emission reduction standard for SCVs.
    Response: We agree with the commenter's suggestion that 
manufacturer guarantees be considered when finalizing the standard. 
Most of the performance tests that are currently available for SCVs are 
based on the previous testing procedures, which are not reflective of 
actual operating conditions. The one performance test we have that is 
based on actual operating conditions is for a facility

[[Page 24128]]

where EtO use exceeds 30 tpy and thus not appropriate for the group of 
facilities at issue here (i.e., those using at least 1 tpy but less 
than 10 tpy of EtO). Therefore, a manufacturer guarantee is appropriate 
to consider in this instance, and a 99.8 percent emission reduction 
standard falls within the manufacturer guarantee range for SCV controls 
as provided by one of the commenters (99.9 percent emission reduction). 
However, this does not change our rationale for a 99.8 percent 
reduction standard during the proposal stage, which was that this is 
the maximum emission SCV 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.
    We disagree with the commenter's recommendation for a maximum 
concentration limit. As discussed in section IV.B.3.a, we are concerned 
that some owners and operators may dilute the air flow of the emissions 
stream to meet a concentration standard, which would not result in any 
actual emission reductions. Furthermore, it is not appropriate to 
establish upper-bound limitations on air flow within this source 
category, as additional flow may be necessary in order to mitigate any 
potential safety issues that may arise. Finally, as discussed in 
section IV.D.3.a, we are not including any alternative, equivalent mass 
rate emission standards in the final rule. Therefore, the commenter's 
concerns regarding the methodology used to calculate the limits are no 
longer relevant.
c. ARVs at Facilities Where EtO Use Is at Least 10 Tpy
    Comment: Several commenters objected to the proposed emission 
reduction standards and stated that they are not achievable as written. 
One commenter stated that we should require emission reduction 
standards based on manufacturer guarantees, along with a maximum 
concentration limit. Another commenter stated that sterilization is a 
batch process and that the concentration from the aeration area is 
subject to constant fluctuation due to differences in product, cycles, 
facility design, and EtO decline curve, which makes a consistent 
emission reduction challenging to determine. Finally, several 
commenters expressed concerns with the use, and our development, of the 
alternative, equivalent mass rate emission standards due to the wide 
variations in ARV parameters across this group of facilities, as well 
as the difficulty in demonstrating compliance with this standard for 
larger facilities.
    Response: We disagree with the commenters' position that the 
proposed emission reduction standards are not achievable. As discussed 
in section III.F.3.a of the proposal preamble (88 FR 22790, April 13, 
2023), most existing sources (i.e., 75 percent) are already achieving 
99.6 percent emission reduction. In addition, 99.9 percent emission 
reduction has been demonstrated by 50 percent of existing sources. We 
also disagree with one commenter's suggestion that manufacturer 
guarantees be considered in this instance for two reasons. First, there 
is no need to rely on manufacturer guaranteed emission levels because 
there are available performance test data for ARVs that are 
representative of actual operating conditions. Unlike SCVs, which go 
through different active phases with wildly varying concentrations, 
fluctuations in ARV concentrations are slight; an aeration room serves 
one purpose, which is to hold product at an elevated temperature, and 
the resulting ARV concentration is relatively constant. Therefore, a 
one-hour test period for this source is appropriate, and the resulting 
performance test data are representative of actual operating 
conditions. To that end, we disagree with another commenter's statement 
that fluctuations in the ARV make it difficult to comply with an 
emission reduction standard. Second, performance test data for ARVs are 
plentiful. As discussed in section III.F.3.a of the proposal preamble, 
there are 47 facilities where EtO use is at least 10 tpy, 41 of which 
have ARVs. Of these 41 facilities, 32 (78 percent) have performance 
test data. Because the performance test data from ARVs at these 
facilities are both plentiful and representative of actual operating 
conditions, there is no need to rely on a manufacturer guaranteed 
emission reduction level in this instance. We also disagree with the 
commenters' recommendation for a maximum concentration standard. As 
discussed in section IV.B.3.a, we are concerned that some owners and 
operators may dilute the air flow of the emissions stream to meet a 
concentration standard, which would not result in any actual emission 
reductions. Furthermore, it is not appropriate to establish upper-bound 
limitations on air flow within this source category, as additional flow 
may be necessary in order to mitigate any potential safety issues that 
may arise. Finally, with respect to the alternative equivalent mass 
rate emission standards, we agree with the commenters' concerns, and we 
are not including these standards in the final rule.
    Comment: One commenter stated that if the lowest practicably 
measured concentration is 30 ppbv (our presumed workable-in-practice 
detection limit for CEMS), then a source with an inlet concentration 
that is too low will be unable to show the required emission reduction, 
even if the control system is providing that level of reduction, 
because the monitoring approach will be unable to distinguish the true 
outlet concentration from 30 ppbv. The commenter further stated that 
existing sources would need to have pre-control aeration room 
concentrations of at least 7.5 ppmv to make this demonstration. Two 
commenters stated that the increased 99.6 percent (existing facilities) 
or 99.9 percent (new facilities) ARV emission reduction standards 
penalize facilities that have reduced EtO concentrations during the 
sterilization cycle. Several commenters noted that facilities have 
reduce EtO concentrations during the sterilization cycle (i.e., use of 
vacuum and/or nitrogen wash cycles) prior to moving the sterilized load 
to aeration to reduce inlet ARV concentrations, and that removals, on a 
percent basis, are only achievable with elevated inlet concentrations.
    Response: One commenter is correct that, given the lowest 
practicable measured concentration (30 ppbv), the pre-control 
concentration would need to be 7.5 ppmv in order to demonstrate 
compliance with the proposed standard for existing sources. The 
performance test data that are available for ARVs at these facilities 
consist of 86 test runs. Of these 86 test runs, only five (six percent) 
had a measured concentration less than 7.5 ppmv, which suggests low 
likelihood that facilities will have difficulty demonstrating 
compliance due to low pre-control concentration. based on the current 
operating conditions Furthermore, regarding the comment that these 
standards would penalize sources who have already worked to reduce 
their EtO concentrations during sterilization and, by extension, their 
inlet ARV concentrations, as discussed in section III.F.3 of the 
proposal preamble, 75 percent of existing sources are already meeting 
the proposed standard; it is unclear, and the commenter does not 
explain, why a requirement that retains facilities' status quo is a 
punishment to those facilities. Most of the industry is either (1) 
currently meeting the proposed standard or (2) capable of meeting the 
proposed standard based on current operating conditions. In addition, 
if a facility with existing ARVs

[[Page 24129]]

wishes to further reduce their EtO concentrations during sterilization, 
then operational changes can be made to the aeration room so that the 
facility can continue to demonstrate compliance with the emission 
reduction standard. Since new facilities are not currently in 
operation, there has been no reduction in EtO concentrations during 
sterilization and, therefore, no penalty has been incurred.
4. What is the rationale for our final approach for the technology 
review?
    Our technology review focused on the identification and evaluation 
of developments in practices, processes, and control technologies that 
have occurred since the standards for Commercial Sterilization 
Facilities were originally promulgated on December 6, 1994 (59 FR 
62585) and further amended on November 2, 2001 (66 FR 55577). 
Specifically, we focused our technology review on all previous 
standards for the various emission sources in the Commercial 
Sterilization Facilities source category, including 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, and ARVs at facilities where EtO 
use is at least 10 tpy. In the proposal, we identified developments for 
all emission sources, and we proposed to revise the standards for these 
emissions sources under the technology review. Further information 
regarding the technology review can be found in the proposed rule (88 
FR 22790, April 13, 2023) and in the supporting materials in the 
rulemaking docket at Docket ID No. EPA-HQ-OAR-2019-0178.
    During the public comment period, we received several comments on 
our proposed determinations for the technology review. No information 
presented by commenters has led us to change our proposed determination 
under CAA section 112(d)(6) for SCVs at facilities where EtO use is at 
least 1 tpy but less than 10 tpy and ARVs at facilities where EtO use 
is at least 10 tpy, and we are finalizing the changes to those 
standards as proposed. For SCVs at facilities where EtO use is at least 
10 tpy, based on comments received on the proposal, we are finalizing a 
99.9 percent emission reduction standard, which is the manufacturer 
guarantee. There is at least one representative performance test 
available for SCVs, but it was conducted at a facility with a higher 
EtO usage rate, and we are unable to determine whether smaller 
facilities can achieve the emission reduction from that performance 
test. The key comments and our specific responses can be found in 
section IV.D.3 of this preamble and in the document, Summary of Public 
Comments and Responses for the Risk and Technology Review for 
Commercial Sterilization Facilities, available in the docket for this 
rulemaking.

E. Amendments Addressing Emissions During Periods of SSM

1. What amendments did we propose to address emissions during periods 
of SSM?
    For all emission points in the Commercial Sterilization Facilities 
source category, we proposed eliminating the SSM exemptions and to have 
the standards apply at all times. More information concerning the 
elimination of SSM provisions is in section III.G. of the proposal 
preamble (88 FR 22790, April 13, 2023).
2. How did the SSM provisions change since proposal?
    We are finalizing the SSM provisions as proposed (88 FR 22790, 
April 13, 2023).
3. What key comments did we receive on the SSM revisions and what are 
our responses?
    This section provides comment summaries and responses for the key 
comments received regarding our proposed revisions. Other comment 
summaries and the EPA's responses for additional issues raised 
regarding these activities as well as issues raised regarding our 
proposed revisions can be found in the document, Summary of Public 
Comments and Responses for the Risk and Technology Review for 
Commercial Sterilization Facilities, available in the docket for this 
rulemaking.
    Comment: One commenter stated that the EPA should consider other 
approaches to adequately account for SSM contingencies. The commenter 
suggested that the EPA classify sources in SSM states as sub-sources 
subject to different emissions limitations or work practice standards. 
Another commenter stated that EtO sterilizers do not create emissions 
during startup or shut down because, unlike other industrial processes 
regulated under the NESHAP program, EtO is not emitted as a byproduct 
of combustion or chemical reaction but is released intentionally in a 
highly controlled manner. The commenter further stated that 
sterilization never begins before control equipment is activated and 
always ends before control equipment is deactivated. Similarly, another 
commenter stated that the EPA inaccurately assumed that startup and 
shutdown are no different than normal operation. The commenter further 
stated that constructing and starting new abatement equipment includes 
periods of troubleshooting and acceptance testing. The commenter also 
stated that the proposal does not address the permit-to-construct 
process and related requirements before transferring to an operating 
permit. Finally, one commenter suggested that the malfunction exemption 
should not be eliminated because, due to the nature of sterilization 
operations and various stages of cycles, commercial sterilizers must be 
able to address malfunctions that could result in a potential risk to 
employees or the facility without the risk of being in noncompliance.
    Response: As discussed in section III.G.1 of the proposal preamble 
(88 FR 22790, April 13, 2023), it is common practice in this source 
category to start an air pollution control device (APCD) prior to 
startup of the emissions source it is controlling, so the APCD would be 
operating before emissions are routed to it, which has been confirmed 
by one of the commenters. In addition, based on responses to the 
December 2019 questionnaire and the September 2021 ICR, many facilities 
already have measures in place to ensure that the emission standards 
are met during periods of SSM, including holding emissions within the 
process unit or the APCD itself, or the use of onsite generators in the 
event of a power outage.\67\ The comments provided do not support 
establishing emission standards that apply only during periods of SSM. 
With respect to classifying sources in SSM states as sub-sources 
subject to different emissions limitations or work practice standards, 
the commenter does not provide any rationale for why this should be 
done or any suggestions for what those emission standards should be. 
With respect to emission spikes from troubleshooting control devices, 
as discussed in section IV.F.3 of this preamble, the EPA is finalizing 
a requirement for emission limits to be based on 30-operating day 
rolling sums of EtO entering the control system(s) for EtO CEMS, which 
will help to mitigate these spikes over time. However, the commenter 
does not provide any rationale for why the permitting process should be 
considering when evaluating SSM. Finally, we cannot agree with the 
commenter's recommendation to keep the malfunction exemption in

[[Page 24130]]

contradiction with Sierra Club v. EPA, 551 F.3d 1019 (D.C. 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. As discussed in section 
III.G.1 of the proposal preamble, in its 2008 decision in Sierra Club 
v. EPA, 551 F.3d 1019 (D.C. Cir. 2008), the court held that emissions 
standards or limitations must be continuous in nature, which means that 
there cannot be exemptions for periods of malfunction. Further, while 
the EPA could consider establishing a different standard during 
malfunction if warranted and still be consistent with the Sierra Club 
decision, the commenter does not provide any specific information 
regarding instances where compliance with the standards during 
malfunction could result in potential risks to the employees or the 
facility or suggestions for what emission standards the EPA should 
consider to address the concern. Therefore, the EPA is not finalizing 
any emission standards that apply only during periods of SSM.
---------------------------------------------------------------------------

    \67\ See memorandum, Review of Startup, Shutdown, and 
Malfunction of Process and APCD Equipment in the Ethylene Oxide 
Commercial Sterilization Source Category Technology Review Project, 
located at Docket ID No. EPA-HQ-OAR-2019-0178.
---------------------------------------------------------------------------

    Comment: One commenter stated that a specific area of concern is 
the ability to demonstrate compliance during startup and shutdown, 
asserting that the proposed rule offered no means for a source to 
remain in compliance during the inevitable and foreseeable, but not 
predictable, failure of monitoring equipment. The commenter further 
suggested that the EPA should consider specific reporting and 
monitoring alternative requirements for these scenarios. The commenter 
provided the example of a requirement specific to releases from 
sterilizer pressure relief devices (PRDs) resulting from malfunctions 
or required during shutdown events that the commenter suggested could 
be modeled after recent PRD requirements in 40 CFR 63.648(j). Another 
commenter recommended that facilities should only be required to report 
malfunction events that result in unpermitted releases to the 
atmosphere. The commenter stated that, in the example situation where 
control equipment unexpectedly goes offline during operations but EtO 
remains trapped within the facilities ducts under negative pressure, 
there would be no need to create additional administrative compliance 
requirements for the facility.
    Response: With respect to accounting for the failure of monitoring 
equipment when demonstrating compliance, as discussed in section IV.F.3 
of this preamble, the EPA is finalizing a minimum data availability 
requirement of 90 percent for EtO CEMS. With respect to specific 
reporting and monitoring alternative requirements that apply during 
periods of SSM, the commenter did not provide any recommendations for 
what those requirements should be. In addition, we agree with one 
commenter's suggestion that facilities should only be required to 
report malfunction events that result in unpermitted releases to the 
atmosphere. However, to be clear, we are finalizing reporting 
requirements for malfunction events that occur with emissions or 
parametric monitoring equipment.
    Comment: One commenter suggested that the EPA should not include 
the general duty clause in the final rule. The commenter stated that it 
is not clear on what basis the EPA is claiming authority to impose a 
general standard of behavior on regulated sources. The commenter 
asserted that CAA section 112 grants the EPA authority to set emissions 
limits and certain specific alternative standards but does not grant 
authority to impose a ``vague and subjective code of conduct.'' The 
commenter stated that the general duty clause is redundant to proposed 
amendment to 40 CFR 63.632(b) that would require compliance ``at all 
times.'' The commenter asserted that if compliance with the specific 
requirements of the rule will satisfy the general duty, then there is 
no need for the EPA to reserve the authority to evaluate a source's 
good air pollution control practices. Furthermore, the commenter 
asserted that the general duty provisions date back to a regulatory 
period during which air quality control rules lacked the specificity of 
monitoring, reporting, and recordkeeping that are included in the 
proposed rule. The commenter suggested that either the EPA should not 
finalize the proposed general duty clause at 40 CFR 63.632(j) or that 
the general duty clause from the General Provisions should be 
incorporated. The commenter stated that the General Provision contains 
language that more clearly explains the EPA's exercise of enforcement 
discretion during SSM periods.
    Response: As part of the proposed rulemaking, we proposed to add 
the following general duty clause to 40 CFR 63.362(j):
    ``At all times, you must operate and maintain any affected source, 
including associated air pollution control equipment and monitoring 
equipment, in a manner consistent with safety and good air pollution 
control practices for minimizing emissions. The general duty to 
minimize emissions does not require the owner or operator to make any 
further efforts to reduce emissions if levels required by the 
applicable standard have been achieved. Determination of whether a 
source is operating in compliance with operation and maintenance 
requirements will be based on information available to the 
Administrator which may include, but is not limited to, monitoring 
results, review of operation and maintenance procedures, review of 
operation and maintenance records, and inspection of the source.''
    We disagree with the commenter's suggestion to not finalize the 
general duty clause. We do not consider this duty clause to be 
redundant just because the emission standards apply at all times; the 
provision imposes a general duty to operate and maintain any affected 
source, including associated air pollution control equipment and 
monitoring equipment, in a manner consistent with safety and good air 
pollution control practices for minimizing emissions. Commenters did 
not provide data supporting the suggestion that this general duty 
clause is redundant. Even assuming it were redundant, which it is not, 
the commenter does not explain why it must be removed. In addition, the 
inclusion of a general duty clause like the one proposed is standard 
practice for other NESHAPs. Furthermore, we disagree with the 
commenter's suggestion to incorporate the general duty clause from 
Subpart A. As discussed in earlier in this section, in its 2008 
decision in Sierra Club v. EPA, 551 F.3d 1019 (D.C. Cir. 2008), the 
court held that under section 302(k) of the CAA, emissions standards or 
limitations must be continuous in nature, which means that there cannot 
be exemptions for periods of SSM. The general duty clause in Subpart A 
contains certain exemptions for periods of SSM. We are therefore 
finalizing the general duty provision as proposed.
4. What is the rationale for our final approach and final decisions to 
address emissions during periods of SSM?
    We evaluated all of the comments on the EPA's proposed amendments 
to the SSM provisions. As explained in section III.G of the proposed 
rule (88 FR 22790, April 13, 2023), in its 2008 decision in Sierra Club 
v. EPA, the court held that under CAA section 302(k), 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. In addition, as part of this rulemaking, 
we have gathered information that indicates many facilities already 
have measures in place to ensure that the emission standards are met 
during periods of

[[Page 24131]]

SSM. Therefore, we determined that these amendments, which remove and 
revise provisions related to SSM, are necessary to be consistent with 
the requirement that the standards apply at all times. More information 
concerning the amendments we are finalizing for SSM is in the preamble 
to the proposed rule and in the comments and our specific responses to 
the comments in the document, Summary of Public Comments and Responses 
for the Risk and Technology Review for Commercial Sterilization 
Facilities, available in the docket for this rulemaking. Therefore, we 
are finalizing our approach for the SSM provisions as proposed.

F. Other Amendments to the Standards

1. What other amendments did we propose for the Commercial 
Sterilization Facilities source category?
    We proposed that owners and operators would be required to 
demonstrate compliance via annual performance testing and parametric 
monitoring of EtO through the use of CEMS. As discussed in section 
III.G.2.c of the proposal preamble (88 FR 22790, April 13, 2023), we 
did not propose to include requirements for fenceline or ambient air 
monitoring as part of this rule for the following reasons:
     Typically for this type of monitoring, we require the 
fenceline monitor to be located at least 50 meters from the source of 
emissions to allow for some dispersion.
     In contrast to the large number of dispersed and 
difficult-to-monitor emission points for other source categories for 
which we have either finalized or proposed fenceline monitoring 
requirements (e.g., refineries), 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.
     The proposed PTE design criteria, room air emission 
standards, and associated parametric monitoring would effectively and 
continuously ensure these previously uncontrolled emissions are 
captured and routed to exhaust points that are then subject to removal 
or emission rate standards.
    With respect to fenceline monitoring, we solicited comment on (1) 
whether fenceline monitoring should be required regardless of the 
proposed PTE design criteria, proposed room air emission standards, and 
proposed 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.
    With respect to ambient air monitoring, we solicited comment on how 
this could be used to screen for elevated concentrations of EtO 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 the commercial sterilization 
proposed rule. We also solicited 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.
    We proposed various changes to the performance testing requirements 
to ensure that the results are as accurate as possible, including the 
approved test methods, requirements for SCV inlet testing, and 24-hour 
test runs for larger users. Furthermore, we proposed various changes to 
the parametric monitoring requirements, as well as requirements for 
demonstrating continuous compliance with the PTE requirements given in 
EPA Method 204.
    We also proposed that owners or operators submit electronic copies 
of required compliance reports (at 40 CFR 63.366(b) and (c)), 
performance test reports (at 40 CFR 63.366(f)), and performance 
evaluation reports (at 40 CFR 63.366(g)) through the EPA's CDX using 
CEDRI, and we proposed two narrow circumstances in which owners or 
operators may, within five business days of the reporting deadline, 
seek extensions of that deadline if they are prevented from reporting 
by conditions outside of their control. We proposed at 40 CFR 63.366(h) 
that an extension may be warranted due to outages of the EPA's CDX or 
CEDRI that precludes an owner or operator from accessing the system and 
submitting required reports. We also proposed at 40 CFR 63.366(i) that 
an extension may be warranted due to a force majeure event, such as an 
act of nature, act of war or terrorism, or equipment failure or safety 
hazards beyond the control of the facility.
    Finally, we proposed to reinstate title V permitting requirements 
for all area source facilities, and we proposed compliance mechanisms 
for owners and operators of combined emission streams. We also proposed 
revisions to clarify text or correct typographical errors, grammatical 
errors, and cross-reference errors.
2. How did the other amendments for the Commercial Sterilization 
Facilities source category change since proposal?
    We are finalizing a requirement for owners and operators to use EtO 
CEMS to demonstrate compliance. In addition, for affected sources with 
a percent emission reduction standard, we are finalizing a requirement 
for source owners or operators to obtain and record hourly average 
ppbvd of EtO concentration, dscfm of flow rate, and weight differential 
in pounds of EtO used, to calculate and record each day of operation--
where any operation less values obtained during periods of SSM 
constitute a day of operation--and the emission limit(s) based on the 
30-operating day rolling sum of EtO entering the control system(s), as 
determined using values from the current operating day and the previous 
29 operating days. However, owners and operators of facilities where 
EtO use is less than 100 lb/year will have the option to demonstrate 
compliance through annual performance testing and parametric 
monitoring. We are not including requirements for fenceline or ambient 
air monitoring in this final rule. For EtO CEMS, based on comments 
received during the proposed rulemaking, we are finalizing a 
requirement for quarterly reporting, as well as a minimum data 
availability of 90 percent. For performance testing, we are finalizing 
the incorporation of additional test methods. Based on comments 
received during the proposed rulemaking, we are also retaining 
currently approved test methods that we proposed to remove, and we are 
not finalizing a requirement to conduct SCV inlet testing. For 
performance test duration, based on comments received during the 
proposed rulemaking, we are not finalizing a requirement for 24-hour 
test runs. Instead, owners and operators may continue to conduct 1-hour 
test runs for ARVs, CEVs, room air emissions, or any combination 
thereof. For emission streams that contain an SCV, we are finalizing a 
requirement for owners and operators to include a representative test 
period as part of their test protocol, which is subject to approval 
from the delegated authority. Based on comments received during the 
proposed rulemaking, we are finalizing numerous revisions to the 
proposed requirements for parametric monitoring. Furthermore, based on 
comments received during the proposed

[[Page 24132]]

rulemaking, we are not finalizing a requirement for owners and 
operators that are required to comply with EPA Method 204 to conduct 
daily inspections of all applicable NDOs. Instead, we a finalizing a 
requirement for owners and operators to demonstrate continuous 
compliance with EPA Method 204 through the use of either outlet 
volumetric flow rate monitors or differential pressure monitors.
    We are not finalizing a requirement for all area source facilities 
to obtain a title V operating permit. In addition, based on comments 
received during the proposed rulemaking, we are finalizing revised 
compliance mechanisms for combined emission streams. We are also 
finalizing an option for owners and operators to demonstrate compliance 
with a site-wide emission limitation, as opposed to demonstrating 
compliance for each individual and combined emission stream.
3. What key comments did we receive on the other amendments for the 
Commercial Sterilization Facilities source category and what are our 
responses?
    Comment: We received extensive comment on our proposal to allow 
either the use of EtO CEMS or annual performance testing with 
parametric monitoring for demonstrating compliance with emission 
standards. Some commenters stated that EtO CEMS should be the only 
mechanism allowed for demonstrating compliance, as it will yield more 
real-time data that will allow for potential issues to be identified 
and resolved more quickly. Other commenters stated that EtO CEMS are a 
relatively new technology and that the available supply, reliability in 
industrial facilities, and maintenance support for EtO CEMS is 
questionable. Commenters also expressed concerns with parametric 
monitoring and pointed to our requirements for CEMS in other rules, as 
well as the fact that EtO CEMS are used in a number of sterilization 
facilities.
    Response: In the majority of instances, parametric monitoring is 
used to good effect as an ongoing means of ensuring that control 
devices continue to get necessary emission reductions. However, given 
the nature of EtO, in which small amounts can have large risk impacts, 
parametric monitoring alone will not be sensitive enough to detect very 
small fluctuations. In addition, many facilities in this source 
category are controlling their EtO emissions using systems that contain 
one or more control devices, each with their own parametric monitoring 
requirements. While this has proven to be effective in reducing EtO 
emissions, it can lead to multiple, simultaneous parameter collection 
and processing, increasing system complexity and increasing the time 
necessary for diagnosis and correction of control device or process 
problems.
    Therefore, the EPA is finalizing a requirement to only use CEMS for 
demonstrating compliance. However, facilities where EtO use is less 
than 100 lb/year will still have the option to use CEMS or performance 
testing and parametric monitoring to demonstrate compliance. This is 
because risk remains at acceptable levels for these facilities even 
when considering uncontrolled emissions. In addition, these facilities 
tend to have relatively simple control systems. Although EtO CEMS is a 
relatively new technology in this industry, it has been proven as a 
highly effective method for demonstrating compliance. While the use of 
these CEMS systems for low-level measurements of EtO is relatively new, 
they are in use in this sector; because of this, we find it technically 
feasible to require their use more broadly. Additionally, the EtO 
instruments used as part of these CEMS are readily available and 
although the low-level detection levels are recent, they have been 
demonstrated in the field.
    Comment: We received extensive comments on our decision to not 
include fenceline or ambient air monitoring as part of the proposed 
rulemaking. Some commenters were supportive of this exclusion, stating 
that this source category is comprised of enclosed facilities with 
defined emission points (e.g., windows, doors, ventilation exhaust) and 
that PTE is sufficient to ensure the containment of emissions. Other 
commenters were opposed to this exclusion, stating that fenceline and 
ambient air monitoring are necessary in order to ensure that commercial 
sterilization facilities are complying with the rule requirements, as 
well as to provide important information about emissions, exposure, and 
the efficacy of control equipment to nearby communities, regulatory 
agencies, and workers. The commenters pointed to other source 
categories where we have either required fenceline monitoring (i.e., 
petroleum refineries) or proposed it (i.e., the Synthetic Organic 
Chemical Manufacturing Industry and the Polymers and Resins industry).
    Response: We acknowledge that many commenters expressed their 
strong support for fenceline monitoring requirements as part of this 
rule. As a general matter, fenceline monitoring is considered a 
particularly useful compliance monitoring approach if it is infeasible 
to enclose an emission source(s). This is the case for source 
categories where we have either required or proposed fenceline 
monitoring, such as refineries, because facilities within these source 
categories cover a wide variety of emission sources where PTE is not 
feasible. At such sources, it is frequently impossible to rapidly 
detect and remedy a leak or other unauthorized release without the use 
of fenceline monitoring.
    By contrast, as discussed in section IV.B.3.c, PTE in accordance 
with EPA Method 204 has been demonstrated to be feasible for commercial 
sterilization facilities. As part of the PTE requirements the EPA is 
finalizing in this rule, the EPA is also requiring monitoring of either 
the volumetric flow rate from each outlet or differential pressure in 
order to ensure that the PTE is operating effectively on a continuous 
basis. Furthermore, as discussed above, we are requiring EtO CEMS at 
facilities where EtO use is at least 100 lb/year, which includes most 
facilities within the source category. The data from these CEMS will 
help to ensure that commercial sterilization facilities are complying 
with the rule requirements, and the data will be made available to the 
public, providing important information about emissions, exposure, and 
the efficacy of control equipment to nearby communities, regulatory 
agencies, and workers. As noted above, the physical configuration of 
commercial sterilizer facilities can also make the implementation of 
fenceline monitoring challenging at these sources. For these reasons, 
the EPA is not finalizing fenceline monitoring requirements as part of 
this rule.
    Comment: We received extensive comments on our proposed requirement 
that EtO CEMS data be reported on a daily basis. Some commenters were 
supportive, stating that daily reporting provides assurance to the 
public that emission control devices are working as designed. Other 
commenters were opposed, stating that facilities need sufficient time 
to conduct QA/QC to verify the accuracy and reliability of the data and 
that reporting inaccurate data due to insufficient QA/QC would 
undermine public confidence of the CEMS monitoring and potentially 
adversely impact the medical supply chain if there is undue public 
concern. One commenter questioned whether there is a precedent for 
daily reporting, and another was unaware of any other NESHAP that 
requires daily reporting for CEMS. Several commenters stated that 
quarterly or semi-annual reporting is sufficient and more consistent 
with other NESHAPs.

[[Page 24133]]

    Response: We agree with the commenters' concern that daily 
reporting of CEMS data is not appropriate. Sufficient time is needed so 
that the proper QA/QC procedures can be conducted to verify the 
accuracy and reliability of the data. Therefore, we are finalizing a 
requirement that CEMS data be reported quarterly, which is consistent 
with other NESHAPs that regulate pollutants of significant concern, as 
well as at least one sterilization facility that uses CEMS to 
demonstrate compliance with local requirements.
    Comment: One commenter stated we did not address CEMS downtime and 
how downtime will be assessed or impact reporting. In addition, two 
commenters stated that there should be allowances or an exemption from 
sampling during periods of non-operation (e.g., power outages, plant 
shutdowns).
    Response: Our general policy is to require source owners and 
operators to have working monitoring while the emissions-producing 
process is operating and to identify those periods where monitoring is 
not working while the emissions-producing process is operating, as well 
as to quickly correct monitoring issues so that such periods are 
minimized. Recognizing that EtO CEMS are a newer technology that may 
pose challenges to users who may be unfamiliar with instrument 
characteristics, the rule will provide a period of data unavailability 
for up to ten percent of process operating time for EtO CEMS in 
operation before requiring additional corrective activity by owners or 
operators. Such an allowance, referred to as a minimum data 
availability requirement, has been used to good effect for other types 
of CEMS as they were introduced. As familiarity with those CEMS 
increased, so did their minimum data availability requirements; the EPA 
expects this pattern to continue for EtO CEMS such that in the future, 
the minimum data availability requirement for EtO CEMS will be replaced 
by the agency's general policy. Until then, the rule will have a 
minimum data availability for EtO CEMS of ninety percent. This means 
that EtO emissions data must be collected over at least ninety percent 
of the process operating time in order to avoid non-compliance and 
potential penalties. Data availability will be determined by assessment 
of the ratio of periods of valid EtO CEMS values to process operation 
periods, where valid EtO CEMS values occur when a minimum of 4 equally 
spaced values occur over an hour of process operation. Periods 
associated with normal quality assurance activities, such as daily 
calibrations, do not count as periods of data unavailability, however, 
periods of out-of-control monitor operation or when the EtO CEMS is 
unable to provide quality-assured data, such as those periods 
associated with monitor or data acquisition and handling system 
failure, do count as periods of data unavailability. Note that source 
owners or operators are to record EtO CEMS values during all periods of 
operation, include SSM, to the extent that the values are available. 
Source owners or operators will need to keep records of periods of 
process operation, EtO CEMS availability, and EtO CEMS unavailability; 
cause and duration of EtO CEMS unavailability; and of activity taken to 
correct and prevent future periods of EtO CEMS unavailability. 
Moreover, owners or operators will be required to provide immediate 
notice of failure to meet the data availability of 90 percent, as well 
as root cause analysis of periods of EtO CEMS monitor unavailability 
and specific corrective actions--along with schedule and enumerated 
expenditures--planned to address EtO CEMS unavailability.
    Comment: Several commenters stated that the requirement to measure 
SCV inlets can create significant safety hazards. Two commenters stated 
that EtO concentrations in abatement system inlets coming from SCVs can 
reach several hundred thousand ppm. The commenters noted that these 
concentrations exceed the lower explosion limit of 30,000 ppm, thereby 
posing a significant explosion risk. Commenters noted that this 
situation could also expose workers to EtO levels above the Immediately 
Dangerous to Life or Health limit set by the U.S. Occupational Safety 
and Health Administration (OSHA), resulting in hazardous working 
conditions. Several commenters stated that we should retain the option 
to determine emission reduction using mass balance calculations and 
pounds of EtO injected into the sterilization chamber to ensure safe 
testing practices.
    Response: We agree with the commenters' concerns regarding the 
safety risks associated with testing the SCV inlet. Therefore, we are 
removing this requirement for SCVs from the final rule. Owners and 
operators must instead determine the mass of EtO emissions from the SCV 
by measuring the daily change in weight of the EtO drums that are used 
to charge the sterilization chamber.
    Comment: Several commenters were opposed to our proposed 
requirement for each performance test run to be conducted over a 24 
hour period for facilities where EtO use is at least 10 tpy, stating 
that this requirement is difficult, infeasible, and of limited value. 
The commenters stated that there are a limited number of testing 
companies with both the experience to conduct performance tests of this 
length, as well as the personnel to remain at facilities during these 
long performance test periods. The commenters stated that multiple 
companies will be in demand for these limited services and that 
scheduling these performance tests so that the medical supply chain is 
not adversely impacted will be difficult. In general, the commenters 
agreed that a performance test run longer than one hour is necessary 
but were divided on what constitutes a representative period, with one 
commenter stating that eight to 10 hours is representative, and another 
stating that six to 12 hours is representative. Several commenters 
stated the performance test duration should be determined by the 
facility and accompanied with a justification of how normal operations 
are captured over this duration. One commenter stated that ARV and room 
air emissions are continuous in nature and that one-hour performance 
test runs are sufficient for these sources. The commenter also stated 
the CEV operations are started and completed within an hour and, 
therefore, one-hour performance test runs are appropriate for these 
sources as well. Finally, one commenter suggested that each performance 
test run for facilities where EtO use is less than 10 tpy should be 
longer than one hour.
    Response: As discussed earlier, we are finalizing a requirement to 
only use EtO CEMS for demonstrating compliance. In addition, owners or 
operators of affected sources subject to a percent emission reduction 
standard will obtain and record EtO concentration in ppbvd, flow rate 
in dscfm, and daily EtO use in pounds; determine daily amounts of EtO 
entering and exiting control systems; use those daily amounts to 
calculate and record 30-operating day rolling sums; and calculate 
emission limits and determine compliance based on those rolling sums. 
However, facilities where EtO use is less than 100 lb/year will still 
have the option to use CEMS or performance testing and parametric 
monitoring to demonstrate compliance. Therefore, our proposal for each 
performance test run to be conducted over a 24-hour period for 
facilities where EtO use is at least 10 tpy is no longer applies and is 
not included in the final rule. For facilities where EtO use is less 
than 100 lb/year, we agree that a one-hour performance test period for

[[Page 24134]]

ARVs and room air emissions is appropriate, as these operations are 
continuous in nature, with minimal variations in emissions. We also 
agree that a one-hour performance test period is appropriate for CEVs, 
as these operations are typically started and concluded in less than 
one hour. For SCVs, the emissions profile can vary significantly 
depending on the number of chambers at a facility and how the emissions 
are staggered. Therefore, we are finalizing a requirement for owners 
and operators to include a representative performance test period for 
SCVs, along with a justification, in their stack test protocol, so that 
the delegated authorities can review and approve or deny the protocol 
as appropriate.
    Comment: We received comments on continuous compliance requirements 
for verifying EPA Method 204. Several commenters contended that 
continuously verifying the direction of airflow through daily 
inspections of each NDO presents significant safety risks and are 
redundant or impractical. They noted that NDOs may be located at 
ceiling levels (such as a makeup air unit) in processing areas or in 
other hard to reach areas where EtO concentrations may require the use 
of specialized protective equipment. One commenter stated that 
streamers are not practical, may not be observable, and often get stuck 
or wrapped around objects. Another commenter noted that smoke testing 
in EtO facilities is discouraged due to safety concerns, as any 
indication of fire in an EtO facility is highly problematic, and seeing 
smoke within the facility should not be routine. Finally, two 
commenters questioned the value of daily NDO inspections when other 
relevant parameters are being continuously monitored.
    One commenter recommended the use of differential pressure 
monitoring to verify EPA Method 204, accompanied by a data recording 
system to demonstrate continuous compliance. Other commenters were 
opposed to any continuous compliance requirements for verifying EPA 
Method 204, stating that they would be burdensome, expensive, and 
difficult to maintain. Two commenters stated that we should change the 
criteria for demonstrating continuous compliance with EPA Method 204 
from ``maintained above 0.007 inches of water'' to ``at least 0.007 
inches of water'' to align to the Method 204 definition of facial 
velocity equivalence.
    Response: We agree with the commenters' concerns regarding the 
safety and practical aspects of daily NDO inspections. Therefore, we 
are not including this requirement in the final rule. In order to 
ensure that emissions are not leaving through uncontrolled spaces, it 
is critical to demonstrate continuous compliance with EPA Method 204. 
In the absence of daily NDO inspections, differential pressure 
monitoring and outlet volumetric flow rate monitoring are viable 
options for verifying the continuous flow of air into a control device, 
and both of these options were included in the proposed rulemaking. 
Therefore, we are finalizing a requirement for owners and operators to 
demonstrate continuous compliance with EPA Method 204 either through 
outlet volumetric flow rate monitoring or through differential pressure 
monitoring. We also agree with commenters that, if differential 
pressure monitoring is used, the pressure differential should be 
maintained at or above 0.007 inch of water in order to demonstrate 
continuous compliance, as this is what is required in EPA Method 204.
    Comment: We received extensive comments on our proposed requirement 
for all area source facilities within the source category to obtain a 
title V operating permit. Several commenters were supportive, citing 
the serious health concerns of EtO. The commenters stated that 
facilities with title V operating permits tend to receive more 
oversight and that this, along with increased community engagement, 
will ensure that these facilities are complying with the rule 
requirements. Other commenters were opposed, stating the current and 
proposed NESHAP included substantial compliance, parametric monitoring, 
recordkeeping, and reporting obligations. One commenter stated that 
subjecting area source EtO commercial sterilizers to the title V 
permitting program requires additional regulatory fees; burdensome 
permitting, recordkeeping and reporting requirements; increased 
administrative costs; as well as Clean Air Act citizen suits. Two 
commenters suggested that the proposed requirements could be 
incorporated into a State minor source permit without the additional 
burden of title V permitting, and that title V permits should apply 
only to major sources. Multiple commenters also indicated that the 
four-factor balancing test still weighs in favor of continued exclusion 
of area source facilities within this source category from title V 
permitting requirements.
    With respect to the first factor (i.e., 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), several commenters stated that requiring 
title V operating permits would not provide significant improvements to 
compliance requirements. Two commenters agreed with our 2005 analysis 
that the NESHAP requirements applicable to area sources already 
subjected them to continuous monitoring and assessment, reporting, and 
certification of compliance status on a semiannual basis, which was 
similar to what was required by title V. Commenters stated that the 
proposed rule addressed increased transparency and further strengthened 
monitoring, recordkeeping, and reporting requirements, including 
developing a new performance specification and associated QA procedures 
for CEMS capable of detecting EtO at very low levels. One commenter 
stated that we recognized that modern NESHAPs have sufficient 
parametric monitoring. The commenter also stated that the only gain 
that we identified that was not already satisfied was the public 
comment period for title V permitting; however, the commenter noted 
that many facilities may need construction permits to come into 
compliance with the updated requirements, during which many States have 
an option to hold a public comment period and a public meeting(s) for 
changes that may be of interest to the community. The commenter noted 
that, as part of this rulemaking process, the EPA held numerous public 
meetings for local communities regarding specific facilities and 
additional public outreach meetings for transparency. This commenter 
stated these outreach efforts and the potential construction permitting 
actions will eliminate the need to have the title V public comment 
period. Three commenters stated that one of the primary purposes of the 
title V program was to clarify in a single document the various and 
complex regulations that applied to a facility in order to improve 
compliance. Two commenters stated that we agreed that EtO sterilizers 
were still subject only to a single NESHAP. Three commenters stated the 
benefit of requiring a title V permit to house all applicable 
regulations into a single document would not apply to those area 
sources and was not needed, and one commenter added that area sources 
should be exempt from title V on that basis alone. One commenter stated 
that, in response to a comment on our 2005 proposed rule, we also 
indicated that NESHAP provisions independently required schedules of 
compliance, provided inspection and entry

[[Page 24135]]

authority, and established emissions limitations and standards that 
were enforceable regardless of title V permitting. This commenter noted 
the proposed rule asserted that the compliance benefits of title V were 
greater today than in 2005 and so the benefits would be greater, but 
the commenter argued that we made these statements without providing 
supporting analysis.
    With respect to the second factor (i.e., 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), several commenters noted that 
requiring area sources to obtain a title V permit would pose 
significant burdens on sterilization facilities, with one commenter 
stating that it would pose significant burden ``within the time frame 
being proposed.'' \68\ Additionally, the commenter stated the State 
permitting agencies may be overly burdened in issuing title V permits 
at a facility with such low emissions. Several commenters stated that 
the proposed title V permitting requirement for area sources would be a 
significant burden for small businesses, as these permits required 
businesses to prepare significant amounts of paperwork, negotiate 
compliance with the permitting authority, and subject their operations 
and permit application to public comment or petitions that would 
potentially delay operations and create additional regulatory burdens 
that, per OMB analysis, may be biased against small businesses. One 
commenter noted that small businesses in this industry had no 
experience with title V permitting and that obtaining these permits 
would require additional resources. The commenter stated that we 
ignored the significant cost of uncertainty that title V permitting 
introduced to small business planning. The commenter explained that 
rather than hiring an engineer to determine how a facility could meet 
the requirements, a small business would have to engage in a process 
with multiple partners, develop supporting material that may or may not 
be sufficient in the eyes of the regulatory authority, and prepare a 
public relations strategy in anticipation of community opposition to 
their operations, and that this investment must be made without the 
certainty of an outcome that will allow continued operation. One 
commenter noted that many Small Business Environmental Assistance 
Programs are precluded from assisting with title V permitees and, as 
such, this rule could strip small businesses of the assistance mandated 
under CAA section 507. One commenter stated that our justification 
seemed premised on an expectation of noncompliance, although clarified 
that we had not alleged that small commercial sterilizers have a 
history of noncompliance. The commenter noted that recent controversies 
around EtO facilities had centered around large facilities owned by 
large businesses. The commenter indicated it was not clear how title V 
permitting of area sources would create additional incentives for 
compliance or give State enforcement authorities the resources and 
expertise they would not otherwise have to enforce this NESHAP. One 
commenter stated the addition of title V permitting for area sources 
formalized community involvement in the authorization of area source 
commercial sterilizers, and that this level of community review was 
unnecessary and overly burdensome. Another commenter noted that the 
public already had access to commercial sterilizer locations, 
emissions, and current standards to which they were subject via our 
website and regulations, as well as our community outreach to advise 
the public of the hazards of EtO.
---------------------------------------------------------------------------

    \68\ Commenter provided the following statement: ``Requiring 
areas sources to obtain a title V permit would pose significant 
burdens on sterilization facilities especially within the time frame 
being proposed.'' (see Docket Item No. EPA-HQ-OAR-2019-0178-0632, 
Attachment 2, page 20).
---------------------------------------------------------------------------

    With respect to the third factor (i.e., 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), two commenters stated there would be no justification 
for imposing the burden of title V permitting. One commenter stated 
that we could have separated the cost estimate for the 86 area sources 
in order to provide more accurate numbers. Additionally, the commenter 
stated that the 2019 cost estimates were not accurate, as the new rules 
would require facilities to change not only their equipment, but also 
their calculation methods, monitoring, and testing. The commenter 
stated that those costs needed to be considered in a title V cost 
analysis. Three commenters stated that our cost estimate for obtaining 
a title V permit underestimated the cost of this requirement and that 
we should not add to the burdens for area sources. One commenter stated 
that the time and cost of getting a title V permit did not correlate to 
the potential gains and that we provided no supporting data for our 
conclusion that the average costs associated with title V ($67,211 for 
the first year, as calculated in 2019) will likely be less for area 
sources. This commenter suggested that our cost determination did not 
align with the proposed rule, which said ``the rule amendments proposed 
provide for a greater degree of complexity and requirements to achieve 
and demonstrate compliance for area sources.'' One commenter noted that 
we stated that the burden was not insignificant, but justified the 
costs because it represented a small portion of the anticipated costs 
related to the amendments of the proposed rule. One commenter stated 
that the analysis on title V applicability did not ask how the burden 
compared to the cost of complying [with] some other measure, but that 
the question was whether the potential compliance benefits outweighed 
the steep costs, the answer to which we seemed to concede was ``no.''
    With respect to the fourth factor (i.e., whether adequate oversight 
by State and local permitting authorities could achieve high compliance 
with the NESHAP requirements without relying on title V permitting), 
one commenter stated that CAA sections 112, 113, and 114 required 
implementation and enforcement programs to be conducted by the EPA or 
delegated to the proper State authority and a small business assistance 
program to assist area sources exempted from title V with compliance. 
The commenter noted that States and the EPA routinely conducted 
voluntary compliance assistance outreach and education programs. The 
commenter noted that the EPA's review of State-provided empirical data 
demonstrated that area sources were adequately compliant with their 
requirements without title V permitting. The commenter stated that the 
proposed rule is silent on whether permitting authorities could 
effectively implement NESHAPs without title V, and that the EPA alluded 
to its 2019 ICR, implying that the responses thereto supported the 
EPA's title V decision, but the EPA never identified specific data or 
explained how it would support any of EPA's cursory statements. The 
commenter concluded that there was no more difficulty enforcing the 
single NESHAP for area sources now versus in 2005, when EPA 
unequivocally determined title V would provide no benefits to its 
ability to enforce CAA regulations in tandem with its State and local 
partners. The commenter stated that requiring title V now would only 
make enforcement more difficult, as State agencies would be flooded 
with

[[Page 24136]]

title V applications that would require time and State funds to 
implement and could potentially shift attention away from major source 
compliance in a way that would compromise (and not improve) 
implementation of any final NESHAP program. Another commenter stated 
there was already sufficient oversight by State and local permitting 
authorities, as well as subpart O requirements. One commenter stated 
that, as a State regulatory agency, they had the ability to adequately 
ensure compliance with the proposed standard for facilities within 
their jurisdiction regardless of whether the facility is subject to 
title V permitting. Another commenter stated the proposed removal of 
the title V permitting exemption for area sources meant a significant 
number of small operations would be required to obtain title V permits 
for the first time, and as many of these area sources were subject to a 
limited set of applicable requirements and permits, there was little 
apparent benefit from the consolidation of these requirements within a 
title V permit. One commenter stated that the EPA failed to discuss 
whether there was a history of noncompliance with the EtO Commercial 
Sterilization NESHAP, which indicated that that there are few potential 
gains from the increased burdens. Finally, one commenter stated that 
State operating permits (e.g., Synthetic Minor or Federally Enforceable 
State Operating Permits) are abundant and adequate to deal with these 
GACT sources without the added expense, complication, and delays 
associated with title V permitting.
    Response: We agree with commenters that the four-factor balancing 
test continues to weigh in favor of exempting area source facilities 
from title V permitting. In particular, we agree with commenters that 
one of the primary benefits of the title V program is to clarify, in a 
single document, the various and complex regulations that apply to a 
facility in order to improve compliance, and that this benefit is not 
realized in this case because commercial sterilization facilities are 
subject to only one NESHAP (Subpart O). In addition, we agree with 
commenters that, in light of the robust monitoring, recordkeeping and 
reporting requirements in the final rule, a title V permit would likely 
not add any substantial monitoring, recordkeeping and reporting 
requirements. We further note that, even in the absence of title V 
permitting requirements, this final rule will ensure transparency 
around the emissions from these facilities by requiring that EtO CEMS 
data be reported on a quarterly basis, and this data will be made 
available to the public.
    In summary, the benefits of requiring title V permitting for area 
source facilities are not outweighed by the concerns. For the reasons 
stated above, we agree with commenters that the four-factor balancing 
test continues to weigh in favor of exempting area source facilities 
from title V permitting on the basis that title V is unnecessarily 
burdensome. Therefore, we are not finalizing title V permitting 
requirements for area source facilities.
    Comment: One commenter suggested that we require only a single 
combined performance test for the outlet point and that the most 
stringent applicable standard (i.e., the control level required for the 
SCV) should be applied. Two commenters stated that our affected source 
proposal is unnecessarily complicated. One commenter stated that where 
control equipment has a single inlet and outlet, the facility should 
not be required to test individual source inlets or outlets. The 
commenter also stated that it is logical that point sources routed to 
the same emission control system should be defined as a single unit. 
The commenter stated it is important to set emission limits that 
reflect this reality and test methods that allow for combined system 
testing at the outlet of the system. The commenter also stated that the 
proposed language implies that the SCV, CEV, and ARV must be tested 
separately, which is challenging given the complexity in design of 
existing duct work and access to inlets. The commenter stated that 
testing the combined inlet to the APCD would be the safest, most 
accurate, and most cost-effective method for determining compliance for 
facilities with combined emissions. Another commenter stated that 
applying the most restrictive removal efficiency standard when 
different sources are combined is impractical.
    Response: The EPA is finalizing approaches that will provide 
facilities with flexibility in terms of how they choose to demonstrate 
compliance with the standards for instances where emission streams are 
combined prior to entering a control system. Facilities can determine 
compliance via one of two options:
     Option 1: Determine the mass of EtO entering the control 
device at a point after the emission streams are combined, and apply 
the most stringent emission reduction standard that the component 
streams are subject to.
     Option 2: Determine the mass of EtO entering the control 
device at points before the emission streams are combined, and apply 
the emission reduction standards that the component streams are subject 
to.
    Option 1 is consistent with what was proposed, and Option 2 has 
been added in order to provide more flexibility for facilities in terms 
of how they chose to demonstrate compliance. As an example, suppose an 
area source facility uses at least 30 tpy but less than 60 tpy, and the 
facility chooses to control all of its ARVs and CEVs with one control 
system. The emission reduction standards that apply to the ARVs and 
CEVs are 99.9% and 99%, respectively. In this example, suppose the mass 
of EtO emissions from the ARVs is 4 lb, and the mass of EtO emissions 
from the CEVs is 1 lb, meaning that the mass of EtO emissions from the 
combined stream is 5 lb. Under Option 1, the facility would need to 
apply an emission reduction of 99.9% to the combined stream, resulting 
in an emission limit of 0.005 lb. Under Option 2, the facility would 
apply an emission reduction of 99.9% to the ARV stream and an emission 
reduction of 99% to the CEV stream, resulting in an emission limit of 
0.014 lb. When an affected source is subject to a relatively high 
emission reduction standard, it can be difficult to demonstrate 
compliance with that standard when the concentration of pollutants 
going into the control device is low. By combining emission streams and 
increasing the concentration of pollutants in the air stream, it is 
easier to demonstrate compliance.
    Comment: One commenter recommended the creation of the option for a 
site-wide emission limitation. This limitation could take the form of 
either overall removal efficiency, or a total mass rate per hour. 
Another commenter suggested a site-wide emission limitation based upon 
EtO usage and end-state emissions and identified as precedent an 
Illinois construction permit containing monthly and annual mass 
emissions caps. The commenter also suggested a compliance option by 
emission reduction or emission rate standards and identified as 
precedent Illinois legislation requiring 99.9 percent emission 
reduction at each exhaust point or limitation of EtO emissions to 0.2 
ppm.
    Response: We agree with the creation of an option for a site-wide 
emission limitation and have included this in the final rulemaking. 
Specifically, we are finalizing two options for determining compliance 
on a site-wide basis:
     Option 1: Determine the mass of EtO being used at the 
facility and apply the SCV emission reduction standard, which is the 
most stringent emission

[[Page 24137]]

reduction standard that any emission stream at the facility is subject 
to.
     Option 2: Determine the mass of EtO being emitted from 
each affected source, and apply the emission reduction standards that 
each affected source is subject to. For SCVs, the mass of EtO may be 
determined by measuring how much is used and then applying a facility-
specific factor that accounts for EtO entering the control systems from 
other affected sources.
    We disagree with the suggestion to set an emissions cap, as the 
amount of EtO that a facility will use in a given month is unknown.
4. What is the rationale for our final approach and final decisions for 
the other amendments for the Commercial Sterilization Facilities source 
category?
    We are not finalizing a requirement for all area sources facilities 
to obtain a title V operating permit, and we are not including 
requirements for fenceline or ambient air monitoring as part of this 
final rule. Based on the comments received during the proposed 
rulemaking, we are requiring EtO CEMS for facilities where EtO use is 
at least 100 lb/year, and we are finalizing a requirement for EtO CEMS 
data to be reported quarterly. We are not finalizing a requirement for 
owners and operators to conduct SCV inlet testing, and we are not 
finalizing a requirement for each performance test run to be conducted 
over a 24-hour period. Lastly, we are finalizing revised compliance 
mechanisms for combined emission streams, as well as the option for 
facilities to demonstrate compliance with a site-wide emission limit, 
as opposed to having to demonstrate compliance for each individual and 
combined emission stream. See section IV.F.3 of this preamble for 
further discussion.
    In a few instances, we received comments that led to additional 
minor editorial corrections and technical clarifications being made in 
the final rule, and our rationale for these corrections and technical 
clarifications can be found in the document, Summary of Public Comments 
and Responses for the Risk and Technology Review for Commercial 
Sterilization Facilities, available in the docket for this rulemaking.

V. Summary of Cost, Environmental, and Economic Impacts and Additional 
Analyses Conducted

A. What are the affected facilities?

    As part of the proposed rulemaking, we estimated that there were 86 
existing commercial sterilization facilities and two planned 
facilities. However, based on comments received on the proposed 
rulemaking, we understand that one of the existing facilities has 
closed. In addition, the commenters identified three existing 
commercial sterilization facilities that were unknown during the 
proposed rulemaking. However, it should be noted that EtO use at the 
three facilities that were previously unknown is very small (i.e., less 
than 1 tpy). A complete list of the known 88 Commercial Sterilization 
Facilities that are affected by this rulemaking is available in 
Appendix 1 of the document, Residual Risk Assessment for the Commercial 
Sterilization Facilities Source Category in Support of the 2024 Risk 
and Technology Review Final Rule, which is available in the docket for 
this rulemaking.

B. What are the air quality impacts?

    At the current level of control prior to the amendments being 
finalized in this action, the EPA estimates that EtO emissions were 
approximately 23 tpy (actuals) and 160 tpy (allowables) from commercial 
sterilization facilities. At the level of control required by the 
amendments being finalized in this action, which includes standards for 
previously unregulated sources and amendments to all sources where 
standards were already in place, we estimated EtO emissions reductions 
of 21 tpy (actuals) and 150 tpy (allowables) for the source category.

C. What are the cost impacts?

    The total capital investment cost of the final amendments and 
standards is estimated to be approximately $313 million in 2021 
dollars. We estimate total annual costs of the final amendments to be 
approximately $74 million.
    The present value (PV) of the estimated compliance costs over the 
20-year timeframe from 2025 to 2044 for the final rule is $773 million 
in 2021 dollars, discounted at a 7 percent rate. The equivalent 
annualized value (EAV) of the costs is $88 million, using a 7 percent 
discount rate. Using a 3 percent discount rate, the PV and EAV of the 
costs from 2025 to 2044 are estimated to be $932 million and $63 
million, respectively.
    The nationwide costs of the different amendments being finalized in 
this action are presented in table 2 of this preamble. As described in 
this preamble, we are finalizing standards for previously unregulated 
sources, as well as amendments for sources where standards were already 
in place. Many of the emissions capture and control technologies that 
are needed to comply with the final rule will impact multiple sources 
at once, and those costs form the basis of our impact estimates. These 
costs are presented in table 2 of this preamble. There are 90 
facilities (including the 88 existing facilities and the two planned 
facilities) affected by the amendments, and the number of facilities 
associated with each of the specific costs is indicated in table 2. The 
facility list was developed using methods described in section II.C of 
the proposal preamble (88 FR 22790, April 13, 2023). A complete list of 
known commercial sterilization facilities is available in Appendix 1 of 
the document, Residual Risk Assessment for the Commercial Sterilization 
Facilities Source Category in Support of the 2024 Risk and Technology 
Review Final Rule, which is available in the docket for this 
rulemaking.

D. What are the economic impacts?

    The economic impact analysis is designed to inform decision makers 
about the potential economic consequences of the compliance costs 
outlined in section V.C of this preamble. The EPA performed a screening 
analysis that compared compliance costs to revenues at the ultimate 
parent company level (several companies own more than one affected 
facility). This is known as the cost-to-revenue or cost-to-sales test, 
or the ``sales test.'' The use of a sales test for estimating small 
business impacts for a rulemaking is consistent with EPA guidance on 
compliance with the Regulatory Flexibility Act (RFA) and is consistent 
with guidance published by the U.S. Small Business Administration's 
Office of Advocacy that suggests that cost as a percentage of total 
revenues is a metric for evaluating cost increases on small entities in 
relation to increases on large entities.
    There are 88 existing commercial sterilization facilities and 2 
planned commercial sterilization facilities, owned by 50 parent 
companies, affected by the final amendments. Of the parent companies, 
22 companies, or 44 percent, are small entities based on the U.S. Small 
Business Administration's table of size standards. Next, we determined 
the magnitude of the costs of the amendments being finalized in this 
action for each entity and then calculated a cost-to-sales ratio for 
each entity by comparing estimated costs to the annual revenues of each 
parent company. We then assessed whether there would be potential for a 
significant impact on small entities based on the cost-to-sales ratios. 
For all entities, the average cost-to-sales ratio is approximately 8 
percent; the median cost-to-sales ratio is 0.2 percent; and the

[[Page 24138]]

maximum cost-to-sales ratio is approximately 69 percent. For large 
firms, the average cost-to-sales ratio is approximately 0.2 percent; 
the median cost-to-sales ratio is 0.03 percent; and the maximum cost-
to-sales ratio is 1.3 percent. This rule has potentially significant 
impacts on small entities. For small firms, the average cost-to-sales 
ratio is approximately 18 percent, the median cost-to-sales ratio is 
4.7 percent, and the maximum cost-to-sales ratio is 69 percent. There 
are 13 small entities (59 percent of all affected small entities) with 
estimated cost-to-sales ratios of 3 percent or greater. 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.
    The EtO sterilization industry is an integral part of the supply 
chain for many medical devices and capacity constraints have been 
reported. Based on the data we analyzed, we expect that the largest 
impacts of this rule are limited to a handful of the companies that 
play a key role in the availability of certain medical devices, and 
several of them are already in the planning stage for additional 
controls.
    Some companies involved in medical device sterilization have 
installed, or are already planning for installation of, additional 
emissions controls. The controls necessary to meet the requirements of 
this final rule include PTEs and gas/solid reactors, along with (in 
some cases) alterations to facility design to ensure adequate capture 
of EtO emissions. Such controls rely on existing technologies that are 
commercially available from manufacturers and are already well 
established in this industry. In addition, a few companies have 
constructed, or are in the process of constructing, new facilities with 
state-of-the-art design and control installations to ensure full 
capture and control of EtO emissions. These early actions by industry 
demonstrate the feasibility of implementing the requirements in this 
final rule.
    Over the last several years, the industry has demonstrated the 
capability to install controls on multiple facilities simultaneously 
without interfering with medical supply chains. For example, three 
companies re-designed their Illinois and Georgia facilities to comply 
with the PTE requirements of EPA Method 204, as well as installed 
emission controls at these facilities during overlapping timeframes 
from May 2019 through August 2020 without disruption to the medical 
supply chain. As discussed in section III.G of this preamble, we have 
reviewed the time that it has taken for these projects to be completed, 
from submission of the initial permit application to installation of 
the continuous compliance mechanisms. Based on this review, we found 
that the process of bringing a facility into compliance with the PTE 
requirements of EPA Method 204, as well as installing and verifying 
additional emission controls, takes approximately a year from permit 
submission to project completion.
    The EPA has evaluated available information about the state of 
control installations at existing commercial sterilization facilities. 
Of the 88 existing facilities, seven appear have already met the 
emission standards and will not need to install additional emission 
controls. Another 55 facilities appear to only need additional 
abatement devices. We expect that 28 facilities still need to meet the 
PTE requirements of EPA Method 204 and install additional abatement 
devices. Table 22 presents the apparent compliance status with the 
final rule for each relevant emission source and facility EtO use 
combination, based on controls that are currently in place.

                 Table 22--Apparent Compliance Status With Final Rule and Compliance Timeframes
----------------------------------------------------------------------------------------------------------------
                                                                                Number of
                                                             Number of          facilities
         Emission source             Facility EtO use     facilities with      appearing to        Compliance
                                                           this affected      achieve final        timeframe
                                                               source          standard \1\
----------------------------------------------------------------------------------------------------------------
SCV..............................  At least 30 tpy.....                 38                 19         Two years.
                                   At least 10 but less                  9                  9         Two years.
                                    than 30 tpy.
                                   At least 1 but less                  18                 16         Two years.
                                    than 10 tpy.
                                   Less than 1 tpy.....                 23                 22       Three years.
ARV..............................  At least 30 tpy.....                 36                 12         Two years.
                                   At least 10 but less                  5                  5       Three years.
                                    than 30 tpy.
                                   At least 1 but less                  10                  7       Three years.
                                    than 10 tpy.
                                   Less than 1 tpy.....                  4                  2       Three years.
CEVs at major source facilities..  N/A.................                  0                N/A       Three years.
CEVs at area source facilities...  At least 60 tpy.....                 25                 12         Two years.
                                   Less than 60 tpy....                 15                  8       Three years.
Group 1 room air emissions at      N/A.................                  0                N/A       Three years.
 major sources.
Group 1 room air emissions at      At least 40 tpy.....                 36                 16         Two years.
 area sources.
                                   Less than 40 tpy....                 38                  7       Three years.
Group 2 room air emissions at      N/A.................                  1                  0       Three years.
 major sources.
Group 2 room air emissions at      At least 20 tpy.....                 44                 17         Two years.
 area sources.
                                   At least 4 but less                  13                  1         Two years.
                                    than 20 tpy.
                                   Less than 4 tpy.....                 27                 27       Three years.
----------------------------------------------------------------------------------------------------------------
\1\ The phrase ``appearing to achieve'' is used (as opposed to ``achieving'') to account for uncertainties in
  the data. A notable example is the SCVs where, for a given facility, the emission reduction on the first
  evacuation may not high enough to ensure that the standard is being met across all evacuations. Another
  uncertainty is the fraction of EtO going to each emission stream. In some instances, there is facility-
  specific information available, and in others, there is no information available and default fractions are
  applied as a result.


[[Page 24139]]

E. What are the benefits?

    The EPA did not monetize the benefits from the estimated emission 
reductions of HAP associated with this final action. The EPA currently 
does not have sufficient methods to monetize benefits associated with 
HAP, HAP reductions, and risk reductions for this rulemaking. However, 
we estimate that the final rule amendments would reduce EtO emissions 
by 21 tons per year and expect that these reductions will lower the 
risk of adverse health effects, including cancer, for individuals in 
communities near commercial sterilization facilities. For example, the 
estimated cancer incidence due to emissions from the source category 
would be reduced from 0.9 to between 0.1 to 0.2, or from 1 cancer case 
every 1.1 years to 1 cancer case every 5 to 10 years.

F. What analysis of environmental justice did we conduct?

    Consistent with applicable executive orders and EPA policy, the EPA 
has carefully analyzed the environmental justice implications of the 
benefits associated with the reductions in EtO emissions as a result of 
this final rule. The EPA conducted this analysis for the purpose of 
providing the public with as full as possible an understanding of the 
potential impacts of this final action. The EPA believes that analyses 
like this can inform the public's understanding, place EPA's action in 
context, and help, identify and illustrate the extent of potential 
burdens and protections.
    As part of understanding the impacts of this source category and of 
this final rule, we examined the potential for the 88 facilities that 
were assessed to pose concerns to communities with EJ concerns both in 
the baseline i.e., under the current standards) standards considered in 
this final rule.
    To examine the potential for EJ concerns in the pre-control 
baseline, we 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 
health risk assessment and 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 final rule for 
the public's understanding.
    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 finalized by this action (``baseline''). 
Again, in this preamble, we present for the public's understanding 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 final rule.
    Overall, the results of the proximity demographic analysis (see 
first three columns of table 23) indicate that the percent of the 
population living within 10 km of the 88 facilities that is Hispanic or 
Latino is substantially higher than the national average (36 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 23 to 25), which presents 
information for individuals 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 
the African American, Hispanic or Latino, below the poverty level, over 
25 and without a high school diploma, and linguistically isolated 
demographic groups are also disproportionally represented at the higher 
risk levels.
    The post-control risk-based demographic analysis presents 
information on current health risks and how the standards considered in 
this final regulatory action would affect the distribution of these 
risks across the populations and communities identified in the 
baseline. The CAA section 112(d)(2), (3), and (5) post-control scenario 
is shown in tables 23 to 25 and the residual risk post-control options 
are shown in tables 26 to 28. 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. We project that a majority of the individuals that 
would remain at risk after implementation of the final standards are 
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 anticipated benefits these final 
standards will have in reducing EtO emissions and associated health 
risks for all of the affected public, including people living in 
communities with EJ concerns. Those benefits include that no individual 
is expected to be exposed to inhalation cancer risk levels above 100-
in-1 million due to emissions from this source category after 
implementation of all the CAA standards finalized in this action.
    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, but a 
synopsis is provided below. We also received comments on the 
demographic analysis. Those comments and our specific responses can be 
found in the document, Summary of Public Comments and Responses for the 
2024 Risk and Technology Review for Commercial Sterilization 
Facilities, available in the docket for this rulemaking.
1. Demographics
    The first three columns of tables 23, 24, and 25 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 17.3 million people live within 10 km of the 88 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 (36 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 in PR are Hispanic or Latino. The percent of the population 
that is ``Other and multiracial'' (11 percent) is higher than the 
national average (8 percent). The percent of people living below the 
poverty level (15 percent) and those over the age of 25 without a high 
school diploma (16 percent) are higher than the national averages (13 
percent and 12 percent, respectively). The percent of people living in 
linguistic isolation \69\ is double

[[Page 24140]]

the national average (10 percent versus 5 percent). 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.
---------------------------------------------------------------------------

    \69\ 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 23, 24, and 25. This analysis 
presented information on the populations living within 10 km of the 
facilities with estimated actual cancer risks greater than or equal to 
1-in-1 million (table 23), greater than or equal to 50-in-1 million 
(table 24), and greater than 100-in-1 million (table 25). The risk 
analysis indicated that emissions from the source category, prior to 
the reductions we are finalizing, expose a total of 5.3 million people 
to a cancer risk greater than or equal to 1-in-1 million around 75 
facilities, 124,000 people to a cancer risk greater than or equal to 
50-in-1 million around 38 facilities, and 19,000 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 more than two times larger than the 
national average (39 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 (124,000 people), and greater 
than 100-in-1 million (19,000 people) are predominantly made up of 
African Americans (43 and 31 percent versus 12 percent nationally), and 
have a higher percentage of the population below the poverty level (22 
and 25 percent versus 13 percent nationally). For this same group, the 
percent over 25 without a high school diploma is above the national 
average (17 and 18 percent versus 12 percent), and linguistic isolation 
is above the national average (9 and 16 percent versus 5 percent). This 
shows that risks tend to be higher both 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 located 
in or near communities 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 
(22 and 26 percent) than the total population living within 10 km (36 
percent Hispanic or Latino) and is above the national average (19 
percent).
    In summary, the baseline risk-based demographic analysis, which 
presents information on those specific locations that are expected to 
have higher cancer risks, suggests that African Americans, those living 
below poverty, and those living in linguistic isolation are 
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 proportion of African Americans (31 
percent), those living below poverty (25 percent) and those living in 
linguistic isolation (16 percent) that is more than twice as large as 
the respective national average.
3. Risks Across Demographics Anticipated After Standards Under CAA 
Sections 112(d)(2), 112(d)(3), and 112(d)(5)
    This analysis presented information on the populations living 
within 10 km of the facilities with estimated cancer risks greater than 
or equal to 1-in-1 million (table 23), greater than or equal to 50-in-1 
million (table 24), and greater than 100-in-1 million (table 25) after 
implementation of standards that we are finalizing 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 23, 24, and 25 titled 
``Baseline and CAA Section 112(d)(2), (3), and (5).'' In this analysis 
we evaluated how the final CAA sections 112(d)(2), (3), and (5) 
emission reductions in this final regulatory action affect the 
distribution of risks identified in the baseline. This enables us to 
characterize the post-control risks and to illustrate for the public's 
understanding whether this part of the final action affects, creates or 
mitigates potential EJ concerns as compared to the baseline.
    The risk analysis indicated that the emissions from the source 
category, after implementation of the standards (resulting in emissions 
reductions) that we are finalizing under CAA sections 112(d)(2), (3), 
and (5), 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 75 facilities to 3.2 million people around 70 
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 124,000 people around 38 facilities to 23,000 people 
around 23 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 19,000 people around 16 facilities to 3,900 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 finalizing under CAA sections 112(d)(2), (3), and (5) 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 twice 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).
    After implementation of the standards that we are finalizing under 
CAA sections 112(d)(2), (3), and (5), the percentage and number of 
African Americans at cancer risks greater than

[[Page 24141]]

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 31 percent or 5,900 people in 
the baseline to 6 percent or 220 people after implementation of the 
final CAA section 112(d)(2), 112(d)(3), and 112(d)(5) emissions 
reductions. It should be noted that while the number of Hispanic or 
Latino people with risks greater than 100-in-1 million was reduced from 
4,900 to 2,600 people, the percentage of the remaining population at 
>100-in-1 million risk that is Hispanic or Latino went up from 26 
percent in the baseline to 68 percent after the final CAA section 
112(d)(2), 112(d)(3), and 112(d)(5) emissions reductions. However,. 
Similarly, the number of people below the poverty level or 
linguistically isolated with a cancer risk >100-in-1 million decreased 
significantly; however, the percentage of the remaining population at 
risk post-emission controls that are in these demographics went up from 
the baseline. 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 (38 percent versus 25 percent), but the 
number of people was reduced from 4,700 people to 560 people.
    In summary, implementation of the final CAA sections 112(d)(2), 
(3), and (5) standards would significantly reduce 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 43 percent in the baseline to about 13 percent after the 
CAA section 112(d)(2), 112(d)(3), and 112(d)(5) 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 23--Comparison at Baseline and CAA Section 112(d)(2), (3), and (5) Post-Control of 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           17.3M            5.3M            3.2M
Number of Facilities............................  ..............              88              75              70
----------------------------------------------------------------------------------------------------------------
                                Race and Ethnicity by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
White...........................................      60 percent      40 percent      40 percent      40 percent
                                                          [197M]          [6.9M]          [2.1M]          [1.3M]
African American................................      12 percent      13 percent      15 percent      16 percent
                                                           [40M]          [2.3M]          [770K]          [520K]
Native American.................................     0.7 percent     0.3 percent     0.3 percent     0.3 percent
                                                            [2M]           [51K]           [17K]            [9K]
Hispanic or Latino (includes white and nonwhite)      19 percent      36 percent      39 percent      38 percent
                                                           [62M]          [6.2M]          [2.1M]          [1.2M]
Other and Multiracial...........................       8 percent      11 percent       7 percent       6 percent
                                                           [27M]          [1.9M]          [350K]          [190K]
----------------------------------------------------------------------------------------------------------------
                                      Income by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Below Poverty Level.............................      13 percent      15 percent      16 percent      16 percent
                                                           [44M]          [2.5M]          [840K]          [520K]
Above Poverty Level.............................      87 percent      85 percent      84 percent      84 percent
                                                          [284M]         [14.8M]          [4.5M]          [2.7M]
----------------------------------------------------------------------------------------------------------------
                                     Education by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Over 25 and without a High School Diploma.......      12 percent      16 percent      18 percent      18 percent
                                                           [40M]          [2.7M]          [960K]          [590K]
Over 25 and with a High School Diploma..........      88 percent       84percent      82 percent      82 percent
                                                          [288M]         [14.6M]          [4.3M]          [2.7M]
----------------------------------------------------------------------------------------------------------------
                              Linguistically Isolated by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Linguistically Isolated.........................       5 percent      10 percent      11 percent      11 percent
                                                           [18M]          [1.8M]          [570K]          [360K]
----------------------------------------------------------------------------------------------------------------
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.
 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.


[[Page 24142]]


    Table 24--Comparison at Baseline and CAA Section 112(d)(2), (3), and (5) Post-Control of 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           17.3M         124,000          23,000
Number of Facilities............................  ..............              88              38              23
----------------------------------------------------------------------------------------------------------------
                                Race and Ethnicity by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
White...........................................      60 percent      40 percent      31 percent      30 percent
                                                          [197M]          [6.9M]           [39K]            [7K]
African American................................      12 percent      13 percent      43 percent      13 percent
                                                           [40M]          [2.3M]           [54K]          [2.9K]
Native American.................................     0.7 percent     0.3 percent     0.1 percent     0.1 percent
                                                            [2M]           [51K]           [190]          [<100]
Hispanic or Latino (includes white and nonwhite)      19 percent      36 percent      22 percent      56 percent
                                                           [62M]          [6.2M]           [27K]           [13K]
Other and Multiracial...........................       8 percent      11 percent       3 percent       2 percent
                                                           [27M]          [1.9M]          [3.9K]           [400]
----------------------------------------------------------------------------------------------------------------
                                      Income by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Below Poverty Level.............................      13 percent      15 percent      22 percent      29 percent
                                                           [44M]          [2.5M]           [28K]          [6.6K]
Above Poverty Level.............................      87 percent      85 percent      78 percent      71 percent
                                                          [284M]         [14.8M]           [96K]           [17K]
----------------------------------------------------------------------------------------------------------------
                                     Education by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Over 25 and without a High School Diploma.......      12 percent      16 percent      17 percent      21 percent
                                                           [40M]          [2.7M]           [21K]            [5K]
Over 25 and with a High School Diploma..........      88 percent      84 percent      83 percent      79 percent
                                                          [288M]         [14.6M]          [103K]           [18K]
----------------------------------------------------------------------------------------------------------------
                              Linguistically Isolated by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Linguistically Isolated.........................       5 percent      10 percent       9 percent      30 percent
                                                           [18M]          [1.8M]           [11K]          [6.9K]
----------------------------------------------------------------------------------------------------------------
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 25--Comparison at Baseline and CAA Section 112(d)(2), (3), and (5) Post-Control of 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           17.3M          19,000           3,900
Number of Facilities............................  ..............              88              16              13
----------------------------------------------------------------------------------------------------------------
                                Race and Ethnicity by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
White...........................................      60 percent      40 percent      40 percent      25 percent
                                                          [197M]          [6.9M]          [7.7K]            [1K]
African American................................      12 percent      13 percent      31 percent       6 percent
                                                           [40M]            [3M]          [5.9K]           [200]
Native American.................................     0.7 percent     0.3 percent     0.1 percent       0 percent
                                                            [2M]           [51K]          [<100]             [0]

[[Page 24143]]

 
Hispanic or Latino (includes white and nonwhite)      19 percent      36 percent      26 percent      68 percent
                                                           [62M]          [6.2M]          [4.9K]          [2.6K]
Other and Multiracial...........................       8 percent      11 percent       3 percent       1 percent
                                                           [27M]          [1.9M]           [500]          [<100]
----------------------------------------------------------------------------------------------------------------
                                      Income by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Below Poverty Level.............................      13 percent      15 percent      25 percent      38 percent
                                                           [44M]          [2.5M]          [4.7K]          [1.4K]
Above Poverty Level.............................      87 percent      85 percent      75 percent      62 percent
                                                          [284M]         [14.8M]           [14K]          [2.4K]
----------------------------------------------------------------------------------------------------------------
                                     Education by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Over 25 and without a High School Diploma.......      12 percent      16 percent      18 percent      22 percent
                                                           [40M]          [2.7M]          [3.5K]           [900]
Over 25 and with a High School Diploma..........      88 percent      84 percent      82 percent      78 percent
                                                          [288M]         [14.6M]           [16K]            [3K]
----------------------------------------------------------------------------------------------------------------
                              Linguistically Isolated by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Linguistically Isolated.........................       5 percent      10 percent      16 percent      44 percent
                                                           [18M]          [1.8M]            [3K]          [1.7K]
----------------------------------------------------------------------------------------------------------------
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. Demographics of Affected Populations Anticipated After 
Implementation of Residual Risk Standards (Post-Control)
    This analysis presented information on the populations living 
within 10 km of the facilities with estimated cancer risks greater than 
or equal to 1-in-1 million (table 26), greater than or equal to 50-in-1 
million (table 27), and greater than 100-in-1 million (table 28) after 
implementation of the standards being finalized under CAA section 
112(f)(2) as described in section IV.C of this preamble. The 
demographic results for the risks after implementation of the residual 
risk-based controls are in the column titled ``Residual Risk 
Standards.'' These standards will be implemented in addition to the CAA 
section 112(d)(2), (3), and (5) standards and are anticipated to result 
in additional post-control emissions reductions. Therefore, in this 
analysis, we evaluated how all of the final standards and emission 
reductions described in this action affect the reduction and 
distribution of risks. This enables us to characterize the post-control 
risks and to understand whether the final action affects, creates or 
mitigates potential EJ concerns as compared to the baseline.
    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 26) is reduced from 3.2 million people after 
implementation of the CAA section 112(d)(2), (3), and (5) controls to 
approximately 700,000 people after implementation of the residual risk 
standards. This represents a significant reduction (about 80 percent 
reduction) in the size of the population facing this level of risk 
after implementation of the residual risk standards being finalized, 
when compared to the population facing this level of risk after 
implementation of just the CAA section 112(d)(2), (3), and (5) 
controls. The people with a cancer risk greater than or equal to 1-in-1 
million are located around 67 facilities after implementation of the 
residual risk standard-based controls.
    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 after implementation of the residual risk standards 
and resulting controls (table 26) 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 nearly twice the national average (34 
percent versus 19 percent), the percent below poverty is above national 
average (15 percent versus 13 percent), the percent over 25 without a 
high school diploma is above the national average (15 percent versus 12 
percent), and the percent linguistic isolation is almost two times the 
national average (11 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 27) is reduced from 23,000 people after 
implementation of the CAA section

[[Page 24144]]

112(d)(2), (3), and (5)-based controls to 170 people after 
implementation of the residual risk-based controls. This represents a 
99 percent reduction in the size of the populations at risk. The people 
living within 10 km of a facility and with a cancer risk greater than 
or equal to 50-in-1 million after implementation of the final rule are 
located around 11 facilities.
    The demographic breakdown of the much smaller 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 the residual risk 
controls (table 27) is significantly different from the population 
after implementation of the CAA section 112(d)(2), (3), and (5) 
controls. Specifically for the 170 individuals still at greater than or 
equal to 50-in-1 million risk, the percent of the population that is 
Hispanic or Latino is significantly higher at 76 percent for the 
residual risk controls. This higher percentage is driven by two 
facilities in Puerto Rico, for which the population is over 99 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 99 percent from 13,000 people to 130 people after anticipated 
implementation of the residual risk standard-based controls. 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 each 
demographic decreased significantly.
    The risk analysis indicated that the number of people living within 
10 km of a facility and exposed to risks greater than 100-in-1 million 
(table 28) is reduced from 3,900 people after implementation of the CAA 
section 112(d)(2), (3), and (5)-based controls to zero people for 
residual risk-based controls. After implementation of the residual risk 
standards, there are no facilities or people with risks greater than 
100-in-1 million. Therefore, there are no greater than 100-in-1 million 
risk populations or demographics to discuss.
    In summary, as shown in the residual risk post-control risk-based 
demographic analysis, the standards being finalized will 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 
residual risk-based controls, the number of Hispanic or Latino people 
that are exposed to risks greater than or equal to 1-in-1 million is 
reduced by 80 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 
99 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, 
or 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 residual risk-based controls, there are no facilities or 
people with risks greater than 100-in-1 million.

  Table 26--Comparison of Demographics for Populations With Cancer Risk Greater Than or Equal to 1-in-1 Million
 Living Within 10 km of Sterilizer Facilities After Implementation of Various Components of the Final Standards
----------------------------------------------------------------------------------------------------------------
                                                                                   Cancer risk >=1-in-1 million
                                                                                 -------------------------------
                                                                                   Post-control
                        Demographic group                           Nationwide      CAA section    Residual risk
                                                                                    112(d)(2),    standards (CAA
                                                                                   (3), and (5)       section
                                                                                     standards      112(f)(2))
----------------------------------------------------------------------------------------------------------------
Total Population................................................            328M            3.2M            700K
Number of Facilities with Pop. Above Cancer Level...............  ..............              70              67
----------------------------------------------------------------------------------------------------------------
                                Race and Ethnicity by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
White...........................................................      60 percent      40 percent      40 percent
                                                                          [197M]          [1.3M]          [280K]
African American................................................      12 percent      16 percent      18 percent
                                                                           [40M]          [520K]          [130K]
Native American.................................................     0.7 percent     0.3 percent     0.2 percent
                                                                            [2M]            [9K]          [2.2K]
Hispanic or Latino (includes white and nonwhite)................      19 percent      38 percent      34 percent
                                                                           [62M]          [1.2M]          [240K]
Other and Multiracial...........................................       8 percent       6 percent       8 percent
                                                                           [27M]          [190K]           [53K]
----------------------------------------------------------------------------------------------------------------
                                      Income by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Below Poverty Level.............................................      13 percent      16 percent      15 percent
                                                                           [44M]          [520K]          [100K]
Above Poverty Level.............................................      87 percent      84 percent      85 percent
                                                                          [284M]            [7M]          [600K]
----------------------------------------------------------------------------------------------------------------
                                     Education by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
> 25 w/o a HS Diploma...........................................      12 percent      18 percent      15 percent
                                                                           [40M]          [590K]          [110K]
> 25 w/HS Diploma...............................................      88 percent      82 percent      85 percent
                                                                          [288M]          [2.7M]          [590K]
----------------------------------------------------------------------------------------------------------------

[[Page 24145]]

 
                              Linguistically Isolated by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Linguistically Isolated.........................................       5 percent      11 percent      11 percent
                                                                           [18M]          [360K]           [80K]
----------------------------------------------------------------------------------------------------------------
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 27--Comparison of Demographics for Populations With Cancer Risk Greater Than or Equal to 50-in-1 Million
    Living Within 10 km of Sterilizer Facilities After Implementation of Various Components of the Final Rule
----------------------------------------------------------------------------------------------------------------
                                                                                   Cancer risk >=50-in-1 million
                                                                                           post-control
                                                                                 -------------------------------
                        Demographic group                           Nationwide      CAA section
                                                                                    112(d)(2),     Residual risk
                                                                                   (3), and (5)      standards
                                                                                     standards      (112(f)(2))
----------------------------------------------------------------------------------------------------------------
Total Population................................................            328M          23,000             170
Number of Facilities with Pop. Above Cancer Level...............  ..............              23              11
----------------------------------------------------------------------------------------------------------------
                                Race and Ethnicity by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
White...........................................................      60 percent      30 percent      12 percent
                                                                          [197M]            [7K]          [<100]
African American................................................      12 percent      13 percent      11 percent
                                                                           [40M]          [2.9K]          [<100]
Native American.................................................     0.7 percent     0.1 percent     0.3 percent
                                                                            [2M]           [190]          [<100]
Hispanic or Latino (includes white and nonwhite)................      19 percent      56 percent      76 percent
                                                                           [62M]           [13K]           [130]
Other and Multiracial...........................................       8 percent       2 percent     0.4 percent
                                                                           [27M]           [400]          [<100]
----------------------------------------------------------------------------------------------------------------
                                      Income by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Below Poverty Level.............................................      13 percent      29 percent      30 percent
                                                                           [44M]          [6.6K]          [<100]
Above Poverty Level.............................................      87 percent      71 percent      70 percent
                                                                          [284M]           [17K]           [120]
----------------------------------------------------------------------------------------------------------------
                                     Education by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
>25 w/o a HS Diploma............................................      12 percent      21 percent      31 percent
                                                                           [40M]            [5K]          [<100]
>25 w/HS Diploma................................................      88 percent      79 percent      69 percent
                                                                          [288M]           [18K]           [120]
----------------------------------------------------------------------------------------------------------------
                              Linguistically Isolated by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Linguistically Isolated.........................................       5 percent      30 percent      47 percent
                                                                           [18M]          [6.9K]          [<100]
----------------------------------------------------------------------------------------------------------------
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.

[[Page 24146]]

 
 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 28--Comparison of Demographics for Populations With Cancer Risk Greater Than 100-in-1 Million Living
       Within 10 km of Sterilizer Facilities After Implementation of Various Components of the Final Rule
----------------------------------------------------------------------------------------------------------------
                                                                                   Cancer risk >100-in-1 million
                                                                                 -------------------------------
                                                                                    CAA section
                        Demographic group                           Nationwide      112(d)(2),     Residual risk
                                                                                   (3), and (5)      controls
                                                                                   post-control
----------------------------------------------------------------------------------------------------------------
Total Population................................................            328M           3,900               0
Number of Facilities with Pop. Above Cancer Level...............  ..............              13               0
----------------------------------------------------------------------------------------------------------------
                                Race and Ethnicity by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
White...........................................................      60 percent      25 percent  ..............
                                                                          [197M]            [1K]
African American................................................      12 percent       6 percent  ..............
                                                                           [40M]           [200]
Native American.................................................     0.7 percent       0 percent  ..............
                                                                            [2M]             [0]
Hispanic or Latino (includes white and nonwhite)................      19 percent      68 percent  ..............
                                                                           [62M]          [2.6K]
Other and Multiracial...........................................       8 percent       1 percent  ..............
                                                                           [27M]          [<100]
----------------------------------------------------------------------------------------------------------------
                                      Income by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Below Poverty Level.............................................      13 percent      38 percent  ..............
                                                                           [44M]          [1.4K]
Above Poverty Level.............................................      87 percent      62 percent  ..............
                                                                          [284M]          [2.4K]
----------------------------------------------------------------------------------------------------------------
                                     Education by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
>25 w/o a HS Diploma............................................      12 percent      22 percent  ..............
                                                                           [40M]           [900]
>25 w/HS Diploma................................................      88 percent      78 percent  ..............
                                                                          [288M]            [3K]
----------------------------------------------------------------------------------------------------------------
                              Linguistically Isolated by Percent [Number of People]
----------------------------------------------------------------------------------------------------------------
Linguistically Isolated.........................................       5 percent      44 percent  ..............
                                                                           [18M]          [1.7K]
----------------------------------------------------------------------------------------------------------------
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''.

VI. Statutory and Executive Order Reviews

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

    This action is a ``significant regulatory action'', as defined 
under section 3(f)(1) of Executive Order 12866, as amended by Executive 
Order 14094. Accordingly, the EPA submitted this action to the Office 
of Management and Budget (OMB) for Executive Order 12866 review. 
Documentation of any changes made in response to the Executive Order 
12866 review is available in the docket. The EPA prepared an analysis 
of the potential costs and benefits associated with this action. This 
analysis, Regulatory Impact Analysis for the Final National Emission 
Standards for Hazardous Air Pollutants: Ethylene Oxide Commercial 
Sterilization and Fumigation Operations, is also available in the 
docket.

B. Paperwork Reduction Act (PRA)

    The information collection activities in this rule have been 
submitted for approval to the Office of Management and Budget (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 amending the reporting and recordkeeping requirements for 
several

[[Page 24147]]

emission sources at commercial sterilization facilities (e.g., SCV, 
ARV, CEV, and room air emissions). The amendments also require 
electronic reporting, removes the SSM exemption, and imposes other 
revisions that affect reporting and recordkeeping. This information was 
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: 88 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. When OMB 
approves this ICR, the Agency will announce that approval in the 
Federal Register and publish a technical amendment to 40 CFR part 9 to 
display the OMB control number for the approved information collection 
activities contained in this final rule.

C. Regulatory Flexibility Act (RFA)

    Pursuant to section 603 of the RFA, the EPA prepared a final 
regulatory flexibility analysis (FRFA) that examines the impact of the 
rule on small entities along with regulatory alternatives that could 
minimize the impact. The complete FRFA is available for review in the 
docket and is summarized here.
1. Statement of Need and Rule Objectives
    This industry is regulated by the EPA because pollutants emitted 
from EtO sterilization and fumigation facilities are considered to 
cause or contribute significantly to air pollution that may reasonably 
be anticipated to endanger public health. This action is being 
finalized to comply with CAA section 112 requirements, which direct the 
EPA to complete periodic reviews of NESHAPs following initial 
promulgation. The requirements are being finalized to address 
unacceptable health risks linked to emissions from subpart O facilities 
and to provide an ample margin of safety to protect public health.
    The EPA is required under CAA section 112(d) to establish emission 
standards for each category or subcategory of major and area sources of 
HAPs listed for regulation in section 112(b). These standards are 
applicable to new or existing sources of HAPs and require the maximum 
degree of emission reduction. The EPA is required to review these 
standards set under CAA section 112 every eight years following their 
promulgation and revise them as necessary, taking into account any 
``developments in practices, processes, or control technologies.'' This 
review is known as the technology review. It has been over 25 years 
since the initial NESHAP for this source category was promulgated in 
1994 and roughly 15 years since the last technology review. As such, 
this final rule is overdue. This rule also establishes standards for 
currently unregulated sources of EtO emissions at subpart O facilities 
under CAA section 112(d), such as room air emissions. The decision in 
Louisiana Environmental Action Network v. EPA, 955 F.3d 1088 (D.C. Cir. 
2020) concluded that the EPA is required to address regulatory gaps 
(i.e., ``gap-filling'') when conducting NESHAP reviews. Finally, the 
EPA determined that a risk review was warranted (despite not being 
required) due to the updated unit risk estimate associated with EtO, 
which is significantly higher than it was during the last review of 
this NESHAP in 2006. Therefore, the EPA is finalizing requirements 
under CAA section 112(f) to address unacceptable health risk attributed 
to emissions from subpart O facilities and to provide an ample margin 
of safety to protect public health.
2. Significant Issues Raised by the Public Comments in Response to the 
Initial Regulatory Flexibility Analysis (IRFA) and EPA Response
    While the EPA did not receive any comments specifically in response 
to the IRFA, we did receive comments from the Office of Advocacy within 
the Small Business Administration (SBA), and a summary of the major 
comments and our responses is provided in the next section. The issues 
raised by SBA were also reflected in comments from small businesses and 
organizations with small business interests.
3. SBA Office of Advocacy Comments and EPA Response
    The SBA's Office of Advocacy (hereafter referred to as 
``Advocacy'') provided substantive comments on the April 2023 Proposal. 
Those comments made the following claims: (1) the proposed compliance 
period for existing sources (18 months) would disadvantage small 
business; (2) the proposed requirement for area source commercial 
sterilization facilities to obtain a title V permit would impose 
significant costs and uncertainty for small businesses; and (3) EPA 
should adopt the BMP alternatives for GACT at area source facilities. 
Based on those claims, Advocacy insisted that EPA reconsider these 
policies to reduce the impact on small entities and reduce the 
likelihood they will leave the market.
    In response to Advocacy's comments, EPA agrees that the proposed 
compliance timeframe is too short and that more time is needed to 
comply with the rule. Therefore, as part of the final rulemaking, EPA 
is providing the maximum amount of time that is allowed under the CAA 
to comply with the emission standards, which is three years for 
standards that are promulgated pursuant to CAA section 112(d) and two 
years for standards that are promulgated pursuant to CAA section 
112(f)(2). With respect to title V permitting, because of the lack of 
other Federal requirements under the CAA that commercial sterilization 
facilities are subject to, as well as the robust monitoring and 
reporting requirements of the final rule, the EPA is not finalizing a 
requirement for area source facilities to obtain a title V permit. In 
addition, with respect to GACT, emission standards were evaluated 
against the BMP on a source-by-source basis. In general, we are 
finalizing the emission standards for each source pursuant to CAA 
section 112(d)(5), with the exception of existing Group 2 room air 
emissions at areas source facilities, because they achieve higher 
emission reductions than the BMP. Further discussion is available in 
section IV.B.3.
    More detailed responses to Advocacy's comments can be found in the 
document, Summary of Public Comments and Responses for the Risk and 
Technology Review for Commercial Sterilization Facilities, available in 
the docket for this rulemaking.
4. Estimate of the Number of Small Entities to Which the Final Rule 
Applies
    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

[[Page 24148]]

industry whose parent company has revenues or numbers of employees 
below the 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 rule contains provisions that will 
affect 22 small entities. These small entities are involved in 
sterilizing various types of medical devices and spices. In addition, 
at least 12 of these small entities are involved in sterilizing the 
types of medical devices discussed in section I.A.1 of this preamble.
5. Projected Reporting, Recordkeeping and Other Compliance Requirements 
of the Final Rule
    Under the rule requirements, small entities will be required to 
comply with various emission standards, which may require the use of 
one or more new control devices. Small entities will also need to 
demonstrate compliance with the emission standards through the use of 
an EtO CEMS or through periodic performance testing and parametric 
monitoring. This rule includes reporting, recordkeeping, and other 
administrative requirements. Under the rule, the EPA estimates that 
approximately 13 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, the EPA 
determined that there is potential for the requirements to have a 
`Significant Impact on a Substantial Number of Small Entities'. See 
section 5.2 of the RIA for more information on the characterization of 
the impacts under the rule.
6. Steps Taken To Minimize Economic Impact to Small Entities
a. Small Business Advocacy Review Panel
    As required by section 609(b) of the RFA, the 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 November 
25, 2020, the EPA's Small Business Advocacy Chairperson convened the 
Panel, which consisted of the Chairperson, the Director of the Sector 
Policies and Programs Division within the 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 SBA.
    Prior to convening the Panel, the 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 and 
developed the findings and discussion summarized in the SBAR report. 
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.
b. Alternatives Considered
    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. The EPA is including 
some of these flexibilities as a part of the rule requirements.
    As discussed in section VI.C.3, the EPA is providing the maximum 
amount of time that is allowed under the CAA to comply with the 
emission standards. In addition, as discussed in section IV.B.3.b, the 
EPA is not any finalizing any mass rate emission standards and is 
finalizing percent emission reduction standards in their place. 
Finally, as discussed in section IV.F.3, the EPA is finalizing 
compliance flexibilities for combined emission streams, as well as the 
option to demonstrate compliance with a site-wide emission limit, as 
opposed to having to demonstrate compliance with each individual or 
combined emission stream.
    In addition, the EPA is preparing a Small Entity Compliance Guide 
to help small entities comply with this rule. The Small Entity 
Compliance Guide will be available on the same date as the date of 
publication of the final rule or as soon as possible after that date 
and will be available on the rule web page at: https://www.epa.gov/stationary-sources-air-pollution/ethylene-oxide-emissions-standards-sterilization-facilities.

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 final action are 
owned or operated by Tribal governments or located within Tribal lands 
within a 10-mile radius. Thus, Executive Order 13175 does not apply to 
this action. We conducted an impact analysis using the latitude and 
longitude coordinates from the risk modeling input file to identify 
Tribal lands within a 10- and 50-mile radius of commercial 
sterilization facilities to determine potential air quality impacts on 
Tribes. Consistent with the EPA Policy on Consultation and Coordination 
with Indian Tribes, although there were no Tribal lands located within 
a 10-mile radius of commercial sterilization facilities, the EPA 
offered consultation with all Tribes that were identified within a 50-
mile radius of an affected facility, however, only one Tribal official 
requested consultation. Additional details regarding the consultation 
letter and distribution list can be found in the memorandum, Commercial 
Sterilization Facilities RTR Consultation Letter, which is available in 
the docket for this rulemaking. The EPA also participated on a phone 
call with the National Tribal Air Association on May 25, 2023, and 
presented an overview of the rulemaking.

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

[[Page 24149]]

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 a 3(f)(1) 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 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.
    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 followed its guidelines and applied age-dependent 
adjustment factors (ADAFs) for early lifestage 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 in this preamble will be particularly beneficial to 
children. In addition, children are at increased risk if they live, 
play, or attend school in close proximity to a commercial sterilization 
facility, of which there are many cases noted by the public to be the 
case. For these reasons, there is both increased susceptibility and 
increased exposure for early lifestages as a result of EtO emissions 
from commercial sterilization facilities.
    A total of 3.97 million children ages 0-17 live within 10km of 
commercial sterilization facilities. Due to baseline emissions from 
commercial sterilization facilities (prior to application of controls 
in this action), there are approximately 1.25 million children (0-17 
years) with increased lifetime cancer risks of greater than or equal to 
1-in-1 million, 30,000 with increased lifetime cancer risks greater 
than or equal to 50-in-1 million, and 4,300 with increased lifetime 
cancer risks greater than 100-in-1 million. After application of the 
controls in this action, lifetime cancer risks to children from 
commercial sterilization facility emissions decrease significantly to 
approximately 162,300 children with increased lifetime cancer risks of 
greater than or equal to 1-in-1 million, less than 100 with increased 
lifetime cancer risks of greater than or equal to 50-in-1 million, and 
none with increased lifetime cancer risks greater than 100-in-1 
million. 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.
    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 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.A and 
IV.C of this preamble and further documented in the risk report, 
Residual Risk Assessment for the Commercial Sterilization Facilities 
Source Category in Support of the 2024 Risk and Technology Review Final 
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 rule 
should be minimal for commercial sterilization facilities and their 
parent companies. EPA was unable to quantify the degree to which 
manufacturers will need to switch sites, so we cannot estimate 
potential energy impacts related to transportation. The EPA solicited 
comment on any potential impacts the proposed standards may have in 
relation to energy use for transportation but did not receive any 
comments that would help to quantify such impacts.

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

    This rulemaking involves technical standards. The EPA conducted 
searches for the standards through the Enhanced National Standards 
Systems Network 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 1, 1A, 2, 2A, 2C, 3A, 3B, and 4 of 40 CFR part 
60, Appendix A, EPA Method 204 of 40 CFR part 51, Appendix M, and EPA 
Methods 301 and 320 in 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 reviewed it as a potential equivalent 
method.
    The EPA incorporates by reference VCS ANSI/ASME PTC 19.10-1981 Part 
10, ``Flue and Exhaust Gas Analyses,'' a method for quantitatively 
determining the gaseous constituents of exhausts resulting from 
stationary combustion and includes a description of the apparatus, and 
calculations used which are used in conjunction with Performance Test 
Codes to determine quantitatively, as an acceptable alternative to EPA 
Method 3B of appendix A to 40 CFR part 60 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. 
This method is available 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.
    The EPA incorporates by reference VCS ASTM D6348-12 (Reapproved 
2020), ``Determination of Gaseous Compounds by Extractive Direct 
Interface Fourier Transform (FTIR) Spectroscopy,'' as an acceptable 
alternative to EPA Method 320 of appendix A to 40 CFR part 63 with 
caveats requiring inclusion of selected annexes to the standard as 
mandatory. The ASTM D6348-12 (R2020) 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. This [filig]eld test method provides near real time 
analysis of extracted gas samples. In the September 22, 2008, NTTAA 
summary, ASTM D6348-03(2010) was determined equivalent to EPA Method 
320 with caveats. ASTM D6348-12 (R2020) is a revised version of ASTM 
D6348-03(2010) and includes a new section on accepting the results from 
direct measurement of a certified spike gas cylinder, but still lacks 
the caveats we placed on the D6348-03(2010) version. We are finalizing 
that the test plan preparation and implementation in the Annexes to 
ASTM D 6348-12 (R2020), Sections Al through A8 are mandatory;

[[Page 24150]]

and in ASTM D6348-12 (R2020) Annex A5 (Analyte Spiking Technique), the 
percent (%) R must be determined for each target analyte (equation 
A5.5). We are finalizing 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 is 
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). The %R value for each compound must be 
reported in the test report, and all field measurements must be 
corrected with the calculated %R value for that compound by using the 
following equation:
[GRAPHIC] [TIFF OMITTED] TR05AP24.001

    The ASTM D6348-12 (R2020) method is available at ASTM 
International, 1850 M Street NW, Suite 1030, Washington, DC 20036. See 
https://www.astm.org/.
    ASTM D3695-88 is already approved for the locations in which it 
appears in the amendatory text.
    While the EPA identified 12 other VCS as being potentially 
applicable, the Agency decided not to use them because these methods 
are impractical as alternatives due to lack of equivalency, 
documentation, validation data, and other important technical and 
policy considerations. The search and review results have been 
documented and are in the memorandum, Voluntary Consensus Standard 
Results for National Emission Standards for Hazardous Air Pollutants: 
Ethylene Oxide Emissions Standards for Sterilization Facilities 
Residual Risk and Technology Review, which is available in the docket 
for this rulemaking.
    Under 40 CFR 63.7(f) and 40 CFR 63.8(f), subpart A--General 
Provisions, a source may apply to the EPA for permission to use 
alternative test methods or alternative monitoring requirements in 
place of any required testing methods, performance specifications, or 
procedures in the final rule or any amendments.

J. Executive Order 12898: Federal Actions To Address Environmental 
Justice in Minority Populations and Low-Income Populations and 
Executive Order 14096: Revitalizing Our Nation's Commitment to 
Environmental Justice for All

    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 communities with EJ concerns. A total of 17.3 million people 
live within 10 km of the 88 facilities that were assessed. The percent 
of the population that is Hispanic or Latino is substantially higher 
than the national average (36 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 the implementation of 
this regulation, cancer risks are unacceptable for several communities. 
See section VI.F for an analysis that characterizes communities living 
in proximity to facilities and risks prior to implementation of the 
final regulation.
    The EPA believes that this action is likely to reduce existing 
disproportionate and adverse effects on communities with EJ concerns. 
This action establishes standards for SCVs and ARVs at facilities where 
EtO use is less than 1 tpy, ARVs at facilities where EtO use is at 
least 1 tpy but less than 10 tpy, CEVs, and room air emissions. In 
addition, it tightens 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 finalizes 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 changes, we expect zero people to be exposed to cancer 
risk levels above 100-in-1 million. See section IV 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 The EPA is also requiring owners and 
operators of commercial sterilization facilities to submit electronic 
copies of required compliance reports, performance test reports, and 
performance evaluation reports, which will increase transparency and 
will provide greater access to information for the public, including 
impacted communities.
    The information supporting this Executive order review is contained 
in section VI.F 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.

K. Congressional Review Act (CRA)

    This action is subject to the CRA, and the EPA will submit a rule 
report to each House of the Congress and to the Comptroller General of 
the United States. This action is not a ``major rule'' as defined by 5 
U.S.C. 804(2).

List of Subjects

40 CFR Part 60

    Environmental protection, Administrative practice and procedures, 
Hazardous substances, Reporting and recordkeeping requirements.

40 CFR Part 63

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

Michael S. Regan,
Administrator.

    For the reasons set forth in the preamble, the EPA amends 40 CFR 
parts 60 and 63 as follows:

PART 60--STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES

0
1. The authority citation for part 60 continues to read as follows:

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

[[Page 24151]]

Appendix B to Part 60--Performance Specifications

0
2. Appendix B to part 60 is amended by adding Performance Specification 
19 to read as follows:

Appendix B to Part 60--Performance Specifications

* * * * *

Performance Specification 19-Performance Specifications and Test 
Procedures for Ethylene Oxide (ETO) Continuous Emission Monitoring 
Systems

1.0 Scope and Application

    1.1 Analyte. This performance specification (PS) is applicable 
for measuring gaseous concentrations of Ethylene Oxide (EtO), CAS: 
775-21-8, on a continuous basis in the units of the applicable 
standard or in units that can be converted to units of the 
applicable standard(s) (e.g., lbs/hr,). This performance 
specification may be approved for the measurement of other 
pollutants and/or in other sectors by the Administrator on a case-
by-case basis if not otherwise allowed or denied in an applicable 
subpart of the regulations.
    1.2 Applicability.
    1.2.1 This specification is used to evaluate the acceptability 
of EtO continuous emission monitoring systems (CEMS) at the time of 
installation or soon after and whenever specified in the 
regulations. The specification includes requirements for initial 
acceptance including instrument accuracy and stability assessments 
and use of audit samples if they are available.
    1.2.2 The Administrator may require the operator, under section 
114 of the Clean Air Act, to conduct CEMS performance evaluations at 
other times besides the initial test to evaluate the CEMS 
performance. See 40 CFR part 60, Sec.  60.13(c) and Sec.  
63.8(e)(1).
    1.2.3 A source that demonstrates their CEMS meets the criteria 
of this PS may use the system to continuously monitor gaseous EtO 
under any regulation or permit that requires compliance with this 
PS. If your CEMS reports the EtO concentration in the units of the 
applicable standard, no additional CEMS components are necessary. If 
your CEMS does not report concentrations in the units of the 
existing standard, then other CEMS (i.e., oxygen) or CEMS components 
(e.g., temperature, stack gas flow, moisture, and pressure) may be 
necessary to convert the units reported by your CEMS to the units of 
the standard.
    1.2.4 These specification test results are intended to be valid 
for the life of the system. As a result, the EtO measurement system 
must be tested and operated in a configuration consistent with the 
configuration that will be used for ongoing continuous emissions 
monitoring.
    1.2.5 Substantive changes to the system configuration require 
retesting according to this PS. Examples of such conditions include 
but are not limited to: major changes in dilution ratio (for 
dilution-based systems); changes in sample conditioning and 
transport, if used, such as filtering device design or materials; 
changes in probe design or configuration and changes in materials of 
construction. Changes consistent with instrument manufacturer 
upgrade that fall under manufacturer's certification do not require 
additional field verification. Manufacturer's upgrades (e.g., 
changes to the quantification algorithm) require recertification by 
the manufacturer for those requirements allowed by this PS, 
including interference, and level of detection (LOD).
    1.2.6 This specification is not designed to evaluate the ongoing 
CEMS performance, nor does it identify specific calibration 
techniques and auxiliary procedures to assess CEMS performance over 
an extended period of time. The requirements in Procedure 7 to 
Appendix F of this part are designed to provide a way to assess CEMS 
and CEMS components (if applicable) performance over an extended 
period of time. The source owner or operator is responsible to 
calibrate, maintain, and operate the CEMS properly.

2.0 Summary of Performance Specification

    2.1 This specification covers the procedures that each EtO CEMS 
must meet during the performance evaluation test. Installation and 
measurement location specifications, data reduction procedures, and 
performance criteria are included.
    2.2 The technology used to measure EtO must provide a distinct 
response and address any appropriate interference correction(s). It 
must accurately measure EtO in a representative sample of stack 
effluent.
    2.3 The relative accuracy (RA) must be established against a 
reference method (RM) (i.e., Method 320, or other alternative 
approved as a RM by the Administrator) on a case-by-case basis if 
not otherwise allowed or denied in an applicable subpart of the 
regulations.
    2.4 A standard addition (SA) procedure using a reference 
standard is included in appendix A to this performance specification 
for use in verifying LOD. For extractive CEMS, where the SA is done 
by dynamic spiking (DS), the appendix A procedure is allowed as an 
option for assessing calibration drift and is also referenced by 
Procedure 7 of appendix F to this part for ongoing quality control 
tests.

3.0 Definitions

    3.1 Calibration drift (CD) means the absolute value of the 
difference between the CEMS output response and an upscale reference 
gas or a zero-level gas, expressed as a percentage of the span 
value, when the CEMS is challenged after a stated period of 
operation during which no unscheduled adjustments, maintenance or 
repairs took place. For other parameters that are selectively 
measured by the CEMS (e.g., temperature, velocity, pressure, flow 
rate) to measure in the units of the applicable standard, use two 
analogous values (e.g., Low: 0-20% of full scale, High: 50-100% of 
full scale). 3.2 Calibration Span means the calibrated portion of 
the measurement range as specified in the applicable regulation or 
another requirement. If the span is not specified in the applicable 
regulation or other requirement, then it must be a value 
approximately equivalent to three times the applicable emission 
standard. When the emission standard is expressed as mass emissions, 
use the average flow rate in the duct to calculate the concentration 
equivalent of the emission standard.
    3.3 Centroidal area means a central area that is geometrically 
similar to the stack or duct cross section and is no greater than 10 
percent of the stack or duct cross-sectional area.
    3.4 Continuous Emission Monitoring System (CEMS) means the total 
equipment required to measure the pollutant concentration or 
emission rate continuously. The system generally consists of the 
following three major subsystems:
    3.4.1 Sample interface means that portion of the CEMS used for 
one or more of the following: Sample acquisition, sample transport, 
sample conditioning, and protection of the monitor from the effects 
of the stack effluent.
    3.4.2 EtO analyzer means that portion of the EtO CEMS that 
measures the total vapor phase EtO concentration and generates a 
proportional output.
    3.4.3 Data recorder means that portion of the CEMS that provides 
a permanent electronic record of the analyzer output. The data 
recorder may record other pertinent data such as effluent flow 
rates, various instrument temperatures or abnormal CEMS operation. 
The data recorder may also include automatic data reduction 
capabilities and CEMS control capabilities.
    3.5 Diluent gas means a major gaseous constituent in a gaseous 
pollutant mixture. For combustion sources, either carbon dioxide 
(CO2) or oxygen (O2) or a combination of these 
two gases are the major gaseous diluents of interest.
    3.6 Dynamic spiking (DS) means the procedure where a known 
concentration of EtO gas is injected into the probe sample gas 
stream for extractive CEMS at a known flow rate to assess the 
performance of the measurement system in the presence of potential 
interference from the flue gas sample matrix.
    3.7 Flow Rate Sensor means that portion of the CEMS that senses 
the volumetric flow rate and generates an output proportional to 
that flow rate. The flow rate sensor shall have provisions to check 
the CD for each flow rate parameter that it measures individually 
(e.g., velocity, pressure).
    3.8 Independent measurement(s) means the series of CEMS data 
values taken during sample gas analysis separated by two times the 
procedure specific response time (RT) of the CEMS.
    3.9 Interference means a compound or material in the sample 
matrix other than EtO whose characteristics may bias the CEMS 
measurement (positively or negatively). The interference may not 
prevent the sample measurement but could increase the analytical 
uncertainty in the measured EtO concentration through reaction with 
EtO or by changing the electronic signal generated during EtO 
measurement.
    3.10 Interference test means the test to detect CEMS responses 
to interferences that are not adequately accounted for in the 
calibration procedure and may cause measurement bias.
    3.11 Level of detection (LOD) means the lowest level of 
pollutant that the CEMS can

[[Page 24152]]

detect in the presence of the source gas matrix interferents with 99 
percent confidence.
    3.12 Measurement error (ME) is the mean difference between the 
concentration measured by the CEMS and the known concentration of a 
reference gas standard, divided by the span, when the entire CEMS, 
including the sampling interface, is challenged.
    3.13 Reference gas standard means the gas mixture containing EtO 
at a known concentration and produced and certified in accordance 
with ``EPA Traceability Protocol for Assay and Certification of 
Gaseous Calibration Standards,'' September 1997, as amended August 
25, 1999, EPA-600/R-97/121 or more recent updates. The tests for 
analyzer measurement error, calibration drift, and system bias 
require the use of calibration gas prepared according to this 
protocol. If a zero gas is used for the low-level gas, it must meet 
the requirements under the definition for ``zero air'' in 40 CFR 
72.2. Alternatively, if the ``protocol'' gas is not commercially 
available, you must use a reference gas that has been prepared 
according to the procedures in appendix B of this PS.
    3.14 Relative accuracy (RA) means the absolute mean difference 
between the gas concentration, or the emission rate determined by 
the CEMS, and the value determined by the RM, plus the confidence 
coefficient of a series of nine test runs, divided by the average of 
the RM or the applicable emission standard.
    3.15 Response time (RT) means the time it takes for the 
measurement system, while operating normally at its target sample 
flow rate, dilution ratio, or data collection rate to respond to a 
known step change in gas concentration, either from a low- or zero-
level to a high-level gas concentration or from a high-level to a 
low or zero-level gas concentration, and to read 95 percent of the 
change to the stable instrument response. There may be several RTs 
for an instrument related to different functions or procedures 
(e.g., DS, LOD, and ME).
    3.16 Span value means an EtO concentration approximately equal 
to two times the concentration equivalent to the emission standard 
unless otherwise specified in the applicable regulation, permit or 
another requirement. Unless otherwise specified, the span may be 
rounded up to the nearest multiple of 5.
    3.17 Stable value means the measure of two or more values that 
are statistically the same and the absence of measurement system 
drift.
    3.18 Standard addition means the addition of known amounts of 
EtO gas (either statically or dynamically) measured sample gas 
stream.
    3.19 Zero gas means a gas with an EtO concentration that is 
below the LOD of the measurement system.

4.0 Interferences

    Sample gas interferences will vary depending on the instrument 
or technology used to make the measurement. Interferences must be 
evaluated through the interference test in this PS. Several 
compounds including carbon dioxide (CO2), carbon monoxide 
(CO), methane (CH4), and water (H2O) are 
potential optical interferences with certain types of EtO monitoring 
technology.
    Note: Interferences may be mitigated though the use of dilution 
systems, however this approach could also affect the sensitivity of 
the measurement.

5.0 Safety

    The procedures required under this PS may involve hazardous 
materials, operations, and equipment. This PS may not address all 
the safety issues associated with these procedures. It is the 
responsibility of the user to establish appropriate safety and 
health practices and determine the applicable regulatory limitations 
prior to performing these procedures. The CEMS user's manual and as 
well as cautions within and materials recommended by the RM should 
be consulted for specific precautions to be taken in regard to the 
relative accuracy testing.

6.0 Equipment and Supplies

    The equipment and supplies are the same as in section 6 of PS 
18, except replace HCl for EtO where appropriate. The following 
definitions are added and/or revised:
    6.1 Moisture Measurement System. If correction of the measured 
EtO emissions for moisture is required, you must install, operate, 
maintain, and quality assure a continuous moisture monitoring system 
for measuring and recording the moisture content of the flue gases. 
The following continuous moisture monitoring systems are acceptable: 
Any optical measurement system validated according to Method 301 or 
section 13.0 of Method 320 in appendix A to part 63 of this chapter; 
a continuous moisture sensor; an oxygen analyzer (or analyzers) 
capable of measuring O2 both on a wet basis and on a dry 
basis; or other continuous moisture measurement methods approved by 
the Administrator.

7.0 Reagents and Standards

    7.1 Reference Gases means the gas mixture containing EtO at a 
known concentration and produced and certified in accordance with 
``EPA Traceability Protocol for Assay and Certification of Gaseous 
Standards, May 2012 (EPA 600/R-12/531) or more recent updates. The 
tests for analyzer measurement error, calibration drift, and system 
bias require the use of calibration gas prepared according to this 
protocol. If a zero gas is used for the low-level gas, it must meet 
the requirements under the definition for ``zero air'' in 40 CFR 
72.2. Alternatively, if the ``protocol'' gas is not commercially 
available, you must use a reference gas that has been prepared 
according to the procedures in appendix B of this PS and meeting the 
requirements in section 12.2 of appendix B of this PS, if 
applicable.
    7.2 Cylinder gas may be diluted for use in this specification, 
including measurement error testing. You must document the 
quantitative introduction of EtO standards into the system using 
Method 205, found in 40 CFR part 51, appendix M, or other procedure 
approved by the Administrator. The laboratory/field evaluations in 
Method 205 must be conducted at least quarterly and prior to any 
audit test (e.g., CGA, RAA) required in QA Procedure 7 (40 CFR part 
60, appendix F). Calibration must be conducted on an annual basis or 
whenever significant changes are made to the dilution system. In 
addition to the requirements in Method 205, when in use, you must 
document gas flow rates through each of the channels; if the 
dilution system records these values electronically, this is 
considered the documentation. For the purpose of this PS, cylinder 
gas should not be diluted beyond a dilution ratio of 500:1 using 
Method 205.

8.0 CEMS Measurement Location Specifications and Pretest Preparation

    8.1 Prior to the start of your initial PS tests, you must ensure 
that the CEMS is installed according to the manufacturer's 
specifications and the requirements in this section.
    8.2 CEMS Installation. Install the CEMS at an accessible 
location where the pollutant concentration or emission rate 
measurements are directly representative of the EtO emissions. If 
the units of the emission standard are expressed as a mass (e.g., 
lb/hr), then the CEMS probe must also be located within 0.5 
equivalent diameters of the flow sensor and the CEMS must be located 
(1) at least two equivalent diameters downstream from the nearest 
control device, the point of pollutant generation, or other point at 
which a change in the pollutant concentration or emission rate may 
occur and (2) at least a half equivalent diameter upstream from the 
effluent exhaust or control device. If the CEMS are to utilize time-
sharing, the distance between each measurement point and the CEMS 
should be approximately the same. The CEMS need not be installed at 
the same location as the relative accuracy test location. If you 
fail the RA requirements in this specification due to the CEMS 
measurement location and a satisfactory correction technique cannot 
be established, the Administrator may require the CEMS to be 
relocated.
    8.2.1 Single point sample gas extraction should be (1) no less 
than 1.0 m (3.3 ft.) from the stack or duct wall or (2) within the 
centroidal area of the stack or duct cross section.
    8.2.2 CEMS and Data Recorder Scale Check. After CEMS 
installation, record and document the measurement range of the EtO 
CEMS. The CEMS operating range and the range of the data recording 
device must encompass all potential and expected EtO concentrations, 
including the concentration equivalent to the applicable emission 
limit and the span value.

9.0 Quality Control--Reserved

10.0 Calibration and Standardization--Reserved

11.0 Performance Specification Test Procedure

    After completing the CEMS installation, setup, and calibration, 
you must complete the PS test procedures in this section. You must 
perform the following procedures and meet the performance 
requirements for the initial demonstration of your CEMS:
    a. Interference Test;
    b. Level of Detection Determination;
    c. Response Time Test;

[[Page 24153]]

    d. Measurement Error Test;
    e. Calibration Drift Test; and
    f. Relative Accuracy Test.
    g. If CEMS is to be time-shared, determine the response time to 
each measurement point, the sampling time at each measurement point, 
and the cycle time at each measurement point. The sampling time at 
each measurement point shall be at least 3 times as long as the 
system response time (RT), and the maximum number of measurement 
points shall not exceed the quotient, rounded down to the next whole 
number, of 15 minutes divided by the longest cycle time of the 
measurement point.
    11.1 Interference Test
    11.1.1 Prior to its initial use in the field, you must 
demonstrate that your monitoring system meets the performance 
requirements of the interference test in section 13.5 of this PS to 
verify that the candidate system measures EtO accurately in the 
presence of common interferences in emission matrices from 
commercial sterilizers. In the event this performance specification 
is applied in other emission sources, the interference test must 
evaluate any other predominant gases is the emission matrices of 
those sources.
    11.1.2 Your interference test must be conducted in a controlled 
environment. The equipment you test for interference must include 
the combination of the analyzer, related analysis software, and any 
sample conditioning equipment (e.g., dilution module, moisture 
removal equipment or other interferent scrubber) used to control 
interferents.
    11.1.3 If you own multiple measurement systems with components 
of the same make and model numbers, you need only perform this 
interference test on one analyzer and associated interference 
conditioning equipment combination. You may also rely on an 
interference test conducted by the manufacturer or a continuous 
measurement system integrator on a system having components of the 
same make(s) and model(s) of the system that you use.
    11.1.4 Perform the interference check using an EtO reference gas 
concentration of approximately ten times the LOD or at 50 parts per 
billion, whichever is greater.
    11.1.5 Introduce the interference test gases listed in table 1 
in section 17.0 of this PS to the analyzer/conditioning system 
separately or in any combination. The interference test gases need 
not be of reference gas quality.
    11.1.6 The interference test must be performed by combining an 
EtO reference gas with each interference test gas (or gas mixture). 
You must measure the baseline EtO response, followed by the response 
after adding the interference test gas(es) while maintaining a 
constant EtO concentration. You must perform each interference gas 
injection and evaluation in triplicate.
    Note: The baseline EtO gas may include interference gases at 
concentrations typical of ambient air (e.g., 21 percent 
O2, 400 parts per million (ppm) CO2, 2 percent 
H2O), but these concentrations must be brought to the 
concentrations listed in table 1 of this PS when their interference 
effects are being evaluated.
    11.1.7 You should document the gas volume/rate, temperature, and 
pressure used to conduct the interference test. A gas blending 
system or manifold may be used.
    11.1.8 Ensure the duration of each interference test is 
sufficient to condition the EtO measurement system surfaces before a 
stable measurement is obtained.
    11.1.9 Measure the EtO response of the analyzer/sample 
conditioning system combination to the test gases in ppbv. Record 
the responses and determine the overall interference response using 
table 2 in section 17.0 of this PS.
    11.1.10 For each interference gas (or mixture), calculate the 
mean difference ([Delta]MCavg) between the measurement 
system responses with and without the interference test gas(es) 
using equation 1 in section 12.2 of this PS. Summarize the results 
following the format contained in table 2 in section 17.
    11.1.11 Calculate the percent interference (I) for the gas runs 
using equation 2 in section 12.2 of this PS.
    11.1.12 The total interference response (i.e., the sum of the 
interference responses of all tested gaseous components) must not 
exceed the criteria set forth in section 13.5 of this PS.
    11.2 Level of Detection Determination
    11.2.1 You must determine the minimum amount of EtO that can be 
detected above the background in a representative gas matrix.
    11.2.2 You must perform the LOD determination in a controlled 
environment such as a laboratory or manufacturer's facility.
    11.2.3 You must add interference gases listed in table 1 of this 
PS to a constant concentration of EtO reference gas.
    11.2.3.1 You may not use an effective reference EtO gas 
concentration greater than ten times the estimated instrument LOD.
    11.2.3.2 Inject the EtO and interferents described in section 
11.1.5 of this PS directly into the inlet to the analyzer, allow 
time for the value to stabilize and then collect measurement data 
for 15 minutes and average those results. Repeat this procedure to 
obtain a total of seven or more of these runs, purging the 
measurement system with ambient air between each run, to determine 
the LOD.
    11.2.4 Calculate the standard deviation of the measured values 
and define the LOD as three times the standard deviation of these 
measurements.
    11.2.5 You must verify the controlled environment LOD of section 
11.2.2 of this PS for your CEMS during initial setup and field 
certification testing using the SA procedure in appendix A of this 
PS with the following exceptions:
    11.2.5.1 You must make three independent SA measurements spiking 
the native source concentration by no more than five times the 
controlled environment LOD concentration determined in section 
11.2.4.
    11.2.5.2 You must perform the SA as a dynamic spike by passing 
the spiked source gas sample through all filters, scrubbers, 
conditioners, and other monitoring system components used during 
normal sampling, and as much of the sampling probe as practical.
    11.2.5.3 The amount detected, or standard addition response 
(SAR), is based on the average difference of the native EtO 
concentration in the stack or duct relative to the native stack 
concentration plus the SA. You must be able to detect the effective 
spike addition (ESA) above the native EtO present in the stack gas 
matrix. The ESA is calculated using equation A7 in appendix A of 
this PS.
    11.2.5.4 If the field verification of your system LOD does not 
demonstrate a SAR greater than or equal to your initial controlled 
environment LOD, you must increase the SA concentration 
incrementally and repeat the field verification procedure until the 
SAR is equal to or greater than LOD. The site-specific standard 
addition detection level (SADL) is equal to the standard addition 
needed to achieve the acceptable SAR, and the SADL replaces the 
controlled environment LOD. The SADL is calculated as the ESA using 
equation A7 in appendix A of this PS. As described in section 13.1 
of this PS, the controlled environment LOD or the SADL that replaces 
a controlled environment LOD must be less than 20 percent of the 
applicable emission limit.
    11.3 Response Time Determination. You must determine ME- and SA-
RT.
    11.3.1 For ME-RT, start the upscale RT determination by 
injecting zero gas into the measurement system as required by the 
procedures in section 11.4 of this PS. For the SA-RT start the 
upscale RT determination at native stack concentration of EtO. Allow 
the value to stabilize, which for the purpose of this PS is a change 
no change greater than 1.0 percent of span or 10 ppbv (whichever is 
greater) for 30 seconds.
    11.3.2 When the CEMS output has stabilized, record the response 
in ppbv, record the time (hh:mm:ss), and immediately introduce an 
upscale (high level) or spike reference gas as required by the 
relevant (ME-RT or SA-RT) procedure. Record the time (hh:mm:ss) 
required for the measurement system to reach 95 percent of the 
change to the final stable value, the difference in these times is 
the upscale RT.
    11.3.3 Reintroduce the zero gas for the ME-RT or stop the 
upscale gas flow for the SA-RT and immediately record the time 
(hh:mm:ss). Record the time (hh:mm:ss) required to reach within 95 
percent of the previous stable response in 11.3.1 or 10 ppbv 
(whichever is greater); the difference in these times is the 
downscale RT.
    Note: For CEMS that perform a series of operations (purge, blow 
back, sample integration, analyze, etc.), you must start adding 
reference or zero gas immediately after these procedures are 
complete.)
    11.3.4 Repeat the entire procedure until you have three sets of 
data, then determine the mean upscale and mean downscale RTs for 
each relevant procedure (from each measurement point if the CEMS is 
time-sharing). Report the greater of the average upscale or average 
downscale RTs as the RT for the system.
    11.4 Measurement Error (ME) Test
    11.4.1 The measurement error test must be performed at the same 
time as the calibration drift test when the system is being placed 
in service. The measurement error test must be performed any time a 
substantive change (see section 1.2.5) has been made to the 
measurement system.
    11.4.1.1 Introduce reference gases to the CEMS probe, prior to 
the sample

[[Page 24154]]

conditioning and filtration system. You may use a gas dilution 
system meeting the requirement in section 7.2 of this PS.
    11.4.1.2 Challenge the measurement system with a zero gas and at 
the three upscale EtO reference gas concentrations in the range 
shown in table 3 of this PS. You may introduce different reference 
gas concentrations in any order, but you must not introduce the same 
gas concentration twice in succession.
    11.4.1.3 Introduce the calibration gas into the sampling probe 
with sufficient flow rate to replace the entire source gas sample 
and continue the gas flow until the response is stable, as evidenced 
when the difference between two consecutive measurements is within 
1.0 percent of span or 5 ppbv (whichever is less). Record this value 
and inject the next calibration gas.
    11.4.1.4 Make triplicate measurements for each reference gas for 
a total of twelve measurements.
    11.4.1.5 At each reference gas concentration, determine the 
average of the three CEMS responses (MCl). Calculate the ME using 
equation 3A in section 12.3.
    11.4.1.6 For non-dilution systems, you may adjust the system to 
maintain the correct flow rate at the analyzer during the test, but 
you may not make adjustments for any other purpose. For dilution 
systems, you must operate the measurement system at the appropriate 
dilution ratio during all system ME checks, and you may make only 
the adjustments necessary to maintain the proper ratio.
    11.4.2 You may use table 5 in section 17.0 to record and report 
your ME test results.
    11.4.3 If the ME specification in section 13.3 is not met for 
all four reference gas concentrations, take corrective action, and 
repeat the test until an acceptable 4-level ME test is achieved.
    11.5 Seven-Day Calibration Drift (CD) Test
    11.5.1 The CD Test Period. Prior to the start of the RA tests, 
you must perform a seven-day CD test. The purpose of the seven-day 
CD test is to verify the ability of the CEMS to maintain calibration 
for each of seven consecutive unit operating days as specified in 
section 11.5.5 of this PS.
    11.5.2 The CD tests must be performed using the zero gas and 
high-level reference gas standards as defined in table 3 of this PS.
    11.5.3 Conduct the CD test on each day during continuous 
operation of the CEMS and normal facility operations following the 
procedures in section 11.7 of this PS, except that the zero gas and 
high-level gas need only be introduced to the measurement system 
once each for the seven days.
    11.5.4 If periodic automatic or manual adjustments are made to 
the CEMS zero and upscale response factor settings, conduct the CD 
test immediately before these adjustments.
    Note: Automatic signal or mathematical processing of all 
measurement data to determine emission results may be performed 
throughout the entire CD process.
    11.5.5 Determine the magnitude of the CD at approximately 24-
hour intervals, for 7 consecutive unit operating days. The 7 
consecutive unit operating days need not be 7 consecutive calendar 
days.
    11.5.6 Record the CEMS response for single measurements of zero 
gas and high-level reference gas. You may use table 6 in section 17 
of this PS to record and report the results of your 7-day CD test. 
Calculate the CD using equation 3B in section 12.3. Report the 
absolute value of the differences as a percentage of the span value.
    11.5.7 The zero-level and high-level CD for each day must be 
less than 5.0 percent of the span value or an absolute difference of 
10 ppbv, as specified in section 13.2 of this PS. You must meet this 
criterion for 7 consecutive operating days.
    11.5.8 Dynamic Spiking Option for Seven-Day CD Test. You have 
the option to conduct a high-level dynamic spiking procedure for 
each of the 7 days in lieu of the high-level reference gas injection 
described in sections 11.5.2 and 11.5.3. If this option is selected, 
the daily zero CD check is still required.
    11.5.8.1 To conduct each of the seven daily mid-level dynamic 
spikes, you must use the DS procedure described in appendix A of 
this PS using a single spike chosen to yield the range as indicated 
in table 3.
    11.5.8.2 You must perform the dynamic spike procedure by passing 
the spiked source gas sample through all filters, scrubbers, 
conditioners, and other monitoring system components used during 
normal sampling, and as much of the sampling probe as practical.
    11.5.8.3 Calculate the high-level CD as a percent of span using 
equation A6 of appendix A to this PS and calculate the zero-drift 
using equation 3B in section 12.3. Record and report the results as 
described in sections 11.5.6 and 11.5.7.
    11.6 Relative Accuracy Test
    11.6.1 Unless otherwise specified in an applicable regulation, 
use Method 320 as the RM for EtO measurement. Conduct the RM tests 
in such a way that they will yield results representative of the 
emissions from the source that can be compared to the CEMS data. You 
must collect gas samples that are at stack conditions (hot and wet), 
and you must traverse the stack or duct as required in section 
11.6.3.
    11.6.2 Conduct the diluent (if applicable), moisture (if 
needed), and pollutant measurements simultaneously. If the emission 
standard is expressed in a mass unit (i.e., lb/hr) you must also 
determine the flowrate simultaneously with each test using Method 2, 
2A, 2B, 2C or 2D in appendix A-1 to this part, as applicable.
    11.6.3 Reference Method Measurement Location and Traverse 
Point(s) Selection.
    11.6.3.1 Measurement Location. Select, as appropriate, an 
accessible RM measurement location at least two equivalent diameters 
downstream from the nearest control device, point of pollutant 
generation, or other point at which a change in the pollutant 
concentration or emission rate may occur, and at least one-half 
equivalent diameter upstream from the effluent exhaust or a control 
device. When pollutant concentration changes are due solely to 
diluent leakage (e.g., air heater leakages) and pollutants and 
diluents are simultaneously measured at the same location, a half 
diameter may be used in lieu of two equivalent diameters. The 
equivalent duct diameter is calculated according to Method 1 in 
appendix A-1 to this part. The CEMS and RM sampling locations need 
not be the same.
    11.6.3.2 Traverse Point Selection. Select traverse points that 
assure acquisition of representative RM samples over the stack or 
duct cross section according to one of the following options: (a) 
sample at twelve traverse points located according to section 11.3 
of Method 1 in appendix A-1 to this part or (b) sample at the three 
traverse points at 16.7, 50.0, and 83.3 percent of the measurement 
line. Alternatively, you may conduct a stratification test following 
the procedures in sections 11.6.3.2.1 through 11.6.3.2.4 to justify 
sampling at a single point. Stratification testing must be conducted 
at the sampling location to be used for the RM measurements during 
the RA test and must be made during normal facility operating 
conditions. You must evaluate the stratification by measuring the 
gas on the same moisture basis as the EtO CEMS (wet or dry). 
Stratification testing must be repeated for each RA test program to 
justify single point.
    11.6.3.2.1 Use a probe of appropriate length to measure the EtO 
concentration, as described in this section, using 12 traverse 
points located according to section 11.3 of Method 1 in appendix A-1 
to this part for a circular stack or nine points at the centroids of 
similarly shaped, equal area divisions of the cross section of a 
rectangular stack.
    11.6.3.2.2 Calculate the mean measured concentration for all 
sampling points (MNavg).
    11.6.3.2.3 Calculate the percent stratification (St) 
of each traverse point using equation 5 in section 12.5.
    11.6.3.2.4 The gas stream is considered to be unstratified and 
you may perform the RA testing at a single point that most closely 
matches the mean if the concentration at each traverse point differs 
from the mean measured concentration for all traverse points by no 
more than 5.0 percent of the mean concentration of EtO or 10 ppbv, 
whichever is less restrictive.
    11.6.4 In order to correlate the CEMS and RM data properly, 
record the beginning and end of each RM run (including the time of 
day in hours, minutes, and seconds) using a clock synchronized with 
the CEMS clock used to create a permanent time record with the CEMS 
output.
    11.6.5 You must conduct the RA test during representative 
process and control operating conditions or as specified in an 
applicable regulation, permit or subpart.
    11.6.6 Conduct a minimum of nine RM test runs.
    Note: More than nine RM test runs may be performed. If this 
option is chosen, up to three test run results may be excluded so 
long as the total number of test run results used to determine the 
CEMS RA is greater than or equal to nine. However, all data must be 
reported including the excluded test runs.
    11.6.7 Analyze the results from the RM test runs using equations 
9 through14 in section 12.6. Calculate the RA between the CEMS 
results and the RM results.

[[Page 24155]]

    11.7 Record Keeping and Reporting
    11.7.1 Record the results of the CD test, the RT test, the ME 
test, and the RA test. Also keep records of the RM and CEMS field 
data, calculations, and reference gas certifications necessary to 
confirm that the performance of the CEMS met the performance 
specifications.
    11.7.2 For systems that use Method 205 to prepare EtO reference 
gas standards, record results of Method 205 performance test field 
evaluation, reference gas certifications, and gas dilution system 
calibration.
    11.7.3 Record the LOD and field verified SADL for the CEMS in 
ppbv.
    11.7.4 Record the results of the interference test.
    11.7.5 Report the results of all certification tests to the 
appropriate regulatory agency (or agencies), in hardcopy and/or 
electronic format, as required by the applicable regulation or 
permit.

12.0 Calculations and Data Analysis

    12.1 Nomenclature.
    Ci = Zero or EtO reference gas concentration used for 
test i (ppbv);
    CC = Confidence coefficient (ppbv);
    CD = Calibration drift (percent);
    davg = Mean difference between CEMS response and the 
reference gas (ppbv);
    di = Difference of CEMS response and the RM value 
(ppbv or units of emission standard, as applicable);
    I = Total interference from major matrix stack gases (percent);
    [Delta]MCavg = Average of the 3 absolute values of 
the difference between the measured EtO calibration gas 
concentrations with and without interference from selected stack 
gases (ppbv);
    MCi = Measured EtO (or zero) reference gas 
concentration i (ppbv);
    MCi = Average of the measured EtO (or zero) reference 
gas concentration i (ppbv);
    MCint = Measured EtO concentration of the EtO 
reference gas plus the individual or combined interference gases 
(ppbv);
    ME = Measurement error for CEMS (percent);
    MNavg = Average concentration at all sampling points 
(ppbv);
    MNbi = Measured native concentration bracketing each 
calibration check measurement (ppbv);
    MNi = Measured native concentration for test or run I 
(ppbv);
    n = Number of measurements in an average value;
    RA = Relative accuracy of CEMS compared to a RM (percent);
    RMavg = Mean measured RM value (ppbv) or units of the 
emission standard);
    RMi = RM concentration for test run i (ppbv or units 
of the emission standard);
    S = Span value (ppmv);
    Sd = Standard deviation of the differences (ppmv);
    Sti = Stratification at traverse point i (percent);
    SADL = Standard addition detection level (ppmv);
    t0.975 = One-sided t-value at the 97.5th percentile 
obtained from table 4 in section 17.0 for n-1 measurements;
    12.2 Calculate the difference between the measured EtO 
concentration with and without interferents for each interference 
gas (or mixture) for your CEMS as:
[GRAPHIC] [TIFF OMITTED] TR05AP24.002

    Calculate the total percent interference as:
    [GRAPHIC] [TIFF OMITTED] TR05AP24.003
    
    12.3 Calculate the ME or CD at Concentration i as:
    [GRAPHIC] [TIFF OMITTED] TR05AP24.004
    
    12.4 Calculate the average native concentration before and after 
each calibration check measurement as:
[GRAPHIC] [TIFF OMITTED] TR05AP24.005

    12.5 Calculate the Percent Stratification at Each Traverse Point 
as:
[GRAPHIC] [TIFF OMITTED] TR05AP24.006


[[Page 24156]]


    12.6 Calculate the RA Using RM and CEMS Data
    12.6.1 Determine the CEMS final integrated average pollutant 
concentration or emission rate for each RM test period. Consider 
system RT, if important, and confirm that the results have been 
corrected to the same moisture, temperature, and diluent 
concentration basis, as applicable. If the emission standard is 
based on a mass emission (i.e., lbs/hr), confirm the results have 
been calculated correctly.
    12.6.3 Make a direct comparison of the average RM results and 
CEMS average value for identical test periods.
    12.6.4 For each test run, calculate the arithmetic difference of 
the RM and CEMS results using equation 6.
[GRAPHIC] [TIFF OMITTED] TR05AP24.007

    12.6.5 Calculate the standard deviation of the differences (Sd) 
of the CEMS measured results and RM results using equation 7.
[GRAPHIC] [TIFF OMITTED] TR05AP24.008

    12.6.6 Calculate the confidence coefficient (CC) for the RA test 
using equation 8.
[GRAPHIC] [TIFF OMITTED] TR05AP24.009

    12.6.7 Calculate the mean difference (davg) between the RM and 
CEMS values in the units of ppbv or of the emission standard using 
equation 9.
[GRAPHIC] [TIFF OMITTED] TR05AP24.010

    12.6.8 Calculate the average RM value using equation 10.
    [GRAPHIC] [TIFF OMITTED] TR05AP24.011
    
    12.6.9 Calculate RA of the CEMS using equation 11.
    [GRAPHIC] [TIFF OMITTED] TR05AP24.012
    
13.0 Method Performance

    13.1 Level of Detection. You may not use a CEMS whose LOD or 
SADL is greater than 20 percent of the applicable regulatory limit 
or other action level for the intended use of the data. If the 
regulatory limit is not based on a concentration, document the 
calculated concentration equivalent as required in section 11.7.
    13.2 Calibration Drift. The zero- and high-level calibration 
drift for the CEMS must not exceed 5.0 percent of the span value or 
an absolute difference of 10.0 ppbv for 7 consecutive operating 
days.
    13.3 Measurement Error. The ME must be less than or equal to 5.0 
percent of the span or an absolute difference of 10.0 ppbv value at 
the low-, mid-, and high-level reference gas concentrations.
    13.4 Relative Accuracy. Unless otherwise specified in an 
applicable regulation or permit, the RA of the CEMS, whether 
calculated in units of EtO concentration or in units of the emission 
standard, must be less than or equal to 20.0 percent of the RM when 
RMavg is used in the denominator of equation 11.
    13.4.1 In cases where the RA is calculated on a concentration 
(ppmv) basis, if the average RM emission level for the test is less 
than 50 percent of the EtO concentration equivalent to the emission 
standard, you may substitute the EtO concentration equivalent to the 
standard in the denominator of equation 14 in place of RMavg.

[[Page 24157]]

    13.4.2 Similarly, if the RA is calculated in units of the 
emission standard and the EtO emission level measured by the RMs is 
less than 50 percent of the emission standard, you may substitute 
the emission standard in the denominator of equation 14 in place of 
RMavg.
    13.4.3 The alternative calculated RA in paragraph 13.4.1 or 
13.4.2 must be less than or equal to 15.0 percent.
    13.5 Interference Test.
    13.5.1 The sum of the interference response(s) from equation 2 
must not be greater than 2.5 percent of the calibration span or 
3.0 percent of the equivalent EtO concentration used for 
the interference test, whichever is less restrictive. The results 
are also acceptable if the sum of the interference response(s) does 
not exceed ten times the LOD or 30 ppbv.

14.0 Pollution Prevention--[Reserved]

15.0 Waste Management--[Reserved]

16.0 Bibliography

    1. ``Method 301--Field Validation of Pollutant Measurement 
Methods from Various Waste Media,'' 40 CFR part 63, appendix A.
    2. EPA Traceability Protocol for Assay and Certification of 
Gaseous Calibration Standards, U.S. Environmental Protection Agency 
office of Research and Development, EPA/600/R-12/531, May 2012.

17.0 Tables, Diagrams, Flowcharts, and Validation Data

              Table 1--Interference Test Gas Concentrations
------------------------------------------------------------------------
                                            Approximate concentration
     Potential interferent gas \1\                 (balance N2)
------------------------------------------------------------------------
CO2....................................  1%  0.2% CO2.
CH4....................................  20  5 ppm.
H2O....................................  5%  1% H2O.\1\
N2.....................................  Balance.\1\
------------------------------------------------------------------------
\1\ Any of these specific gases can be tested at a lower level if the
  manufacturer has provided reliableness for limiting or scrubbing that
  gas to a specified level in CEMS field installations.


              Table 2--Example Interference Test Data Sheet
------------------------------------------------------------------------
 
------------------------------------------------------------------------
Date of Test
------------------------------------------------------------------------
Analyzer type
------------------------------------------------------------------------
Model Number
------------------------------------------------------------------------
Serial Number
------------------------------------------------------------------------
Span
------------------------------------------------------------------------
Test Organization
------------------------------------------------------------------------
Test Personnel
------------------------------------------------------------------------


----------------------------------------------------------------------------------------------------------------
                                              EtO        EtO concentration      Absolute
   Interference gas or combination       concentration     w/interference      difference      Average absolute
                                            (ppbv)             (ppbv)            (ppbv)       difference  (ppbv)
----------------------------------------------------------------------------------------------------------------
 
                                      ------------------------------------------------------
 
                                      ------------------------------------------------------
 
----------------------------------------------------------------------------------------------------------------
 
                                      ------------------------------------------------------
 
                                      ------------------------------------------------------
 
----------------------------------------------------------------------------------------------------------------
 
                                      ------------------------------------------------------
 
                                      ------------------------------------------------------
 
----------------------------------------------------------------------------------------------------------------
 
                                      ------------------------------------------------------
 
                                      ------------------------------------------------------
 
----------------------------------------------------------------------------------------------------------------
 
                                      ------------------------------------------------------
 

[[Page 24158]]

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


                                          Table 3--Performance Specification Test Zero and Reference Gas Ranges
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                         EtO zero and reference gas concentrations  in terms of percent of
                                                                                                     span \a\
                  Test                               Units            ----------------------------------------------------------------------   Section
                                                                                    Zero               Low level    Mid-level    High level
--------------------------------------------------------------------------------------------------------------------------------------------------------
Calibration Drift.......................  % Of Span..................  2.0 percent or calculate the flow using a stable 
tracer gas included in your spike gas standard.
    8.2.4.2 If you use flow measurements to determine the spike 
dilution, then use equation A1 in section 11.2.1 of this appendix 
PS-19A to calculate the DF. Determination of the spike dilution 
requires measurement of EtO spike flow (Qspike) and total 
flow through the CEM sampling system (Qprobe).
    8.2.4.3 If your CEMS is capable of measuring an independent 
stable tracer gas, you may use a spike gas that includes the tracer 
to determine the DF using equation A2 or A3 (sections 11.2.2 and 
11.2.3 of this appendix PS-19A) depending on whether the tracer gas 
is also present in the native source emissions.
    8.2.4.4 For extractive CEMS, you must correct the background 
measurements of EtO for the dilution caused by the addition of the 
spike gas standard. For spiking systems that alternate between 
addition of EtO and zero gas at a constant DF, the background 
measurements between spikes will not be equal to the native source 
concentration.
    8.2.5 Begin by collecting unspiked sample measurements of EtO. 
You must use the average of two unspiked sample measurements as your 
pre-spike background.
    Note: Measurements should agree within 5.0 percent or three 
times the level of detection to avoid biasing the spike results.
    8.2.5.1 Introduce the EtO gas spike into the permanent CEMS 
probe, upstream of the particulate filter or sample conditioning 
system and as close to the sampling inlet as practical.
    8.2.5.2 Maintain the EtO gas spike for at least twice the DS 
response time of your CEMS or until the consecutive measurements 
agree within 5.0 percent. Collect two independent measurements of 
the native plus spiked EtO concentration.
    8.2.5.3 Stop the flow of spike gas for at least twice the DS 
response time of your CEMS or until the consecutive measurements 
agree within 5.0 percent. Collect two independent measurements of 
the native EtO concentration.
    8.2.6 Repeat the collection of sample measurements in section 
8.2.5 until you have data for each spike concentration including a 
final set of unspiked sample measurements according to section 
8.2.5.3.
    8.2.7 Verify that the CEMS responded as expected for each spike 
gas injection, and that the data quality is not impacted by large 
shifts in the native source concentration. Discard and repeat any 
spike injections as necessary to generate a complete set of the 
required replicate spike measurements.
    8.2.8 Calculate the standard addition response (SAR) for 
extractive CEMS, using equation A4 in section 11.2, of this appendix 
PS-19A.
    8.2.9 If the DS results do not meet the specifications for the 
appropriate performance test in PS-19 or Procedure 7 of appendix F 
of this part, you must take corrective action and repeat the DS 
procedure.

9.0 Quality Control--Reserved

10.0 Calibration and Standardization--Reserved

11.0 Calculations and Data Analysis

    Calculate the SA response for each measurement and its 
associated native EtO measurement(s), using equations in this 
section. (Note: For cases where the emission standard is expressed 
in units of lb/hr or corrected to a specified O2 or 
CO2 concentration, an absolute accuracy specification 
based on a span at stack conditions may be calculated using the 
average concentration and applicable conversion factors. The 
appropriate procedures for use in cases where a percent removal 
standard is more restrictive than the emission standard is the same 
as in PS-2, sections 12 and 13, in this appendix.)
    11.1 Nomenclature.
    Cspike = Actual EtO reference gas concentration 
spiked (e.g., bottle or reference gas concentration) ppmv;
    Ctracer spiked = Tracer gas concentration injected 
with spike gas (``reference concentration'') ppmv;
    DF = Spiked gas dilution factor;
    DSCD = Calibration drift determined using DS procedure 
(percent);
    DSE = Dynamic spike error (ppmv);
    ESA = Effective spike addition (ppmv);
    MCSA = Measured SA-elevated source gas concentration 
(ppmv);
    MCspiked = Measured EtO reference gas concentration i 
(ppmv);
    MCnative = Average measured concentration of the 
native EtO (ppmv);

[[Page 24161]]

    Mnative tracer = Measured tracer gas concentration 
present in native effluent gas (ppmv);
    Mspiked tracer = Measured diluted tracer gas 
concentration in a spiked sample (ppmv);
    Qspike = Flow rate of the dynamic spike gas (Lpm);
    Qprobe = Average total stack sample flow through the 
system (Lpm);
    S = Span (ppmv);
    SAR = Standard addition response (ppmv)
    11.2 Calculating Dynamic Spike Response and Error.
    11.2.1 If you determine your spike DF using spike gas and stack 
sample flow measurements, calculate the DF using equation A1:
[GRAPHIC] [TIFF OMITTED] TR05AP24.013

    11.2.2 If you determine your spike DF using an independent 
stable tracer gas that is not present in the native source 
emissions, calculate the DF for DS using equation A2:
[GRAPHIC] [TIFF OMITTED] TR05AP24.014

    11.2.3 If you determine your spike dilution factor using an 
independent stable tracer that is present in the native source 
emissions, calculate the dilution factor for dynamic spiking using 
equation A3:
[GRAPHIC] [TIFF OMITTED] TR05AP24.015

    11.2.4 Calculate the SA response using equation A4:
    [GRAPHIC] [TIFF OMITTED] TR05AP24.016
    
    11.2.5 Calculate the DS error using equation A5.
    [GRAPHIC] [TIFF OMITTED] TR05AP24.017
    
    11.2.6 Calculating CD using DS. When using the DS option for 
determining mid-level CD, calculate the CD as a percent of span 
using equation A6:
[GRAPHIC] [TIFF OMITTED] TR05AP24.018

    11.2.7 The effective spike addition (ESA) is the expected 
increase in the measured concentration as a result of injecting a 
spike. Calculate ESA using equation A7:
[GRAPHIC] [TIFF OMITTED] TR05AP24.019

12.0 Reserved

13.0 Tables and Figures

                     Table A13--1--Spike Data Sheet
------------------------------------------------------------------------
 
------------------------------------------------------------------------
Facility Name:                   Date:                Time:
------------------------------------------------------------------------
Unit(s) Tested:                  Personnel:
------------------------------------------------------------------------
Analyzer Make and Mode
------------------------------------------------------------------------

[[Page 24162]]

 
Serial Number
------------------------------------------------------------------------
Calibration Span
------------------------------------------------------------------------


--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                               MCnative                         Actual value (ppb)
                                         Qspike                -----------------------------------------------------------------------------
            Qprobe (lpm)                 (lpm)        DF \1\                                            Cspike \2\                            DSE (ppbv)
                                                                    Pre          Post         Avg.                        MCspike \3\
--------------------------------------------------------------------------------------------------------------------------------------------------------
 
--------------------------------------------------------------------------------------------------------------------------------------------------------
 
--------------------------------------------------------------------------------------------------------------------------------------------------------
 
--------------------------------------------------------------------------------------------------------------------------------------------------------
 
--------------------------------------------------------------------------------------------------------------------------------------------------------
 
--------------------------------------------------------------------------------------------------------------------------------------------------------
 
--------------------------------------------------------------------------------------------------------------------------------------------------------
 
--------------------------------------------------------------------------------------------------------------------------------------------------------
 
--------------------------------------------------------------------------------------------------------------------------------------------------------
 
--------------------------------------------------------------------------------------------------------------------------------------------------------
 
--------------------------------------------------------------------------------------------------------------------------------------------------------
 
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                     Average
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                     SD
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ DF must be less than or equal to 10%.
\2\ Cspike = Actual EtO concentration of the spike gas, ppbv.
\3\ MCspike = Measured EtO concentration of the spiked sample at the target level, ppbv.

PS-19 Appendix B Preparation and Certification of Ethylene Oxide Gas 
Standards

1.0 Scope and Application

    1.1 This appendix (appendix PS-19B) to Performance Specification 
19 (PS-19) describes the procedure and performance criteria for the 
preparation and certification of EtO Gas Manufacturer Primary 
Standards (GMPS) and Gas Manufacturer Alternative Certified 
Standards (GMACS). These procedures are not specific to ethylene 
oxide and could be transferable to the preparation of gas standards 
for other pollutants regulated under 40 CFR parts 59, 60, 61, 63, 
and 65.

2.0 Summary of the Appendix

    EPA requires the use of EPA Protocol gas standards for emissions 
monitoring. These gases are established following the EPA 
Traceability Protocol for Assay and Certification of Gaseous 
Standards, May 2012 (EPA 600/R-12/531) otherwise referred in this 
appendix PS-19B as the EPA Traceability Protocol. The EPA 
Traceability Protocol requires the use of certified reference gas 
standards directly traceable to National Institute of Standards and 
Technology (NIST) or other recognized national metrology institute 
(NMI) reference gas standards. A NIST certified value is a value for 
which NIST has the highest confidence in that all known or suspected 
sources of bias and imprecision have been accounted for. Without 
NIST or other NMI reference gas standards, the necessary EPA 
Protocol gas standards cannot be prepared. An alternative approach 
is needed to establish a gas standard functionally equivalent to the 
EPA Protocol gas standard when NIST or NMI reference gas standard 
are not available. This appendix PS-19B is intended to provide 
procedures and performance criteria for the establishment of Gas 
Manufacturer Alternative Certified Standards (GMACS), the functional 
equivalent of EPA Protocol gas standards. GMACS and Gas Manufacturer 
Primary Standards (GMPS), the functional equivalent of the NIST or 
NMI reference gas standards. The GMPS are the reference gases used 
to establish the certified concentrations of the GMACs. The GMPS are 
established using a dual certification approach where the 
gravimetrically prepared reference value is confirmed using an 
independent measurement approach traceable to the International 
System of Units (SI) and references materials or devices.
    2.1 This appendix PS-19B is intended to be performance-based and 
allow specialty gas manufacturers (SGM) flexibility in the 
preparation and certification of GMPS and GMACS.
    2.2 This appendix PS-19B is not intended to be a replacement for 
the EPA Protocol gases established according to the EPA Traceability 
Protocol when calibration gases that meet EPA Traceability Protocol 
requirements are available. When NIST or other recognized NMI 
reference gas standards are manufactured and readily available, 
those gases must be used.
    2.3 This appendix PS-19B is reliant on the procedures included 
the EPA Traceability Protocol for Assay and Certification of Gaseous 
Standards, May 2012 (EPA 600/R-12/531). Users of this appendix PS-
19B for the preparation of GMPS and GMACS must be proficient with 
the preparation protocol cylinders using this standard.

    Note: This appendix PS-19B does not require the user to 
participate in any protocol gas verification program.

    2.4 Any alternatives to the procedures in this appendix PS-19B 
are subject to Administrator review under the alternative test 
method the authority to approve alternatives or changes to test 
methods specified in the General Provisions to 40 CFR parts 60, 61, 
and 63 (Sec. Sec.  60.8(b)(2), 61.13(h)(1)(ii), and 63.7(e)(2)(ii)). 
Requests for alternative to the procedures must be submitted to the 
agency according to Guideline Document 22 (https://www.epa.gov/system/files/documents/2022-09/gd-022r5.pdf).

3.0 Definitions

    3.1 Certification means a set of procedures and performance 
criteria used by a SGM to prepare and certify a GMPS and/or GMACS 
for commercial sale.
    3.2 Certified Reference Material or CRM means a material that 
has been certified or verified by either NIST or other NMI (e.g., 
VSL, NPL) and may be used for traceability purposes.
    3.3 Dual Method Certification means a process in which the 
gravimetric value is independently confirmed by a measured value.
    3.4 EPA Protocol Gas means a calibration or reference gas 
required for emissions monitoring directly traceable to NIST or

[[Page 24163]]

other accepted NMI reference gas standards, prepared following the 
EPA Traceability Protocol
    3.5  EPA Traceable Protocol for Assay and Calibration Gas 
Standards or commonly referred to as the ``EPA Traceability 
Protocol'' means the document The protocol allows producers of these 
standards, users of gaseous standards, and other analytical 
laboratories to establish traceability of EPA Protocol Gases to 
gaseous reference standards produced by the National Institute of 
Standards and Technology (NIST).
    3.6  Gas Calibration Cylinder means a refillable cylinder that 
meets the applicable DOT/TC specifications for high pressure 
cylinders. The cylinders shall be permanently stamped with a unique 
value.
    3.7 Gas Manufacturer Alternative Certified Standards or GMACS 
means a gas that has been prepared according to this procedure and 
serves as a functional substitute for an EPA Protocol Gas where EPA 
Protocol gases are not available.
    3.8 Gas Manufacturer Intermediate Standard means a gas reference 
standard made by a gas supplier and certified according to the U.S. 
EPA protocol rules for GMISs. For the purpose of this Appendix, 
GMISs may be assayed against a GMPS.
    3.9  Gas Manufacturer Primary Standards or GMPS means a 
reference gas standard prepared and certified by the SGM that serves 
as a functional substitute for the reference gas standards 
established by, but not yet available from NIST or other accepted 
NMI and required by the EPA Traceability Protocol to produce EPA 
Protocol gases.
    3.10  Gravimetry means the quantitative measurement of an 
analyte by weight.
    3.11  NIST means the National Institute of Standards and 
Technology, located in Gaithersburg, Maryland.
    3.12 NIST Traceable Reference Material or NTRM means is a 
reference material produced by a commercial supplier with a well-
defined traceability linkage to NIST and named by NIST procedures, 
on a batch rather than individual basis. This linkage is established 
via criteria and protocols defined by NIST that are tailored to meet 
the needs of the metrological community to be served.
    3.13 Primary Reference Materials or PRM means a mixture 
composition is verified against VSL's own primary standard gas 
mixtures to confirm the assigned value.
    3.14 Protocol Gas means a calibration or reference gas required 
for emissions monitoring traceable to NIST or other accepted NMI, 
prepared following the EPA Traceability Protocol.
    3.15 Research Gas Mixture or RGMs means a reference material 
produced by a commercial supplier certified by NIST on an individual 
basis, often using non routine procedures, are called Research Gas 
Mixtures (RGMs), and may be used for traceability purposes.
    3.16 Specialty Gas Manufacturer or SGM means an organization 
that prepares and certified gas calibration gas mixtures.
    3.17 International System of Units or SI means the standards for 
international measurement and are comprised of length (meter), time 
(second), amount of substance (mole), electric current (ampere), 
temperature (kelvin), luminous intensity (candela), and mass 
(kilogram).
    3.18 Standard Reference Material or SRM means a material or 
substance issued by NIST that meets NIST-specific certification 
criteria and is issues with that with a certificate or certificate 
of analysis that reports the results of its characterizations and 
provides information regarding the appropriate use(s) of the 
material.
    3.19 Uncertainty means the expression of the statistical 
dispersion of the values attributed to a measured quantity. For the 
purpose of this appendix, uncertainty is calculated using the root 
sum square of all uncertainty budget items associated with each 
procedure at k=2 (i.e., approximately 95 confidence).
    3.20 VSL means Van Swinden National Lab, located in Delft, 
Netherlands.

4.0 Interferences--Reserved

5.0 Safety

    The procedures required under this appendix may involve 
hazardous materials, operations, and equipment. This procedure may 
not address all of the safety problems associated with these 
procedures. You as the facility or operator must establish 
appropriate safety and health practices and determine the applicable 
regulatory limitations prior to performing these procedures. You 
should consult instrument operation manuals, material safety data 
sheets, compressed gas safety requirements, and other Occupational 
Safety and Health Administration regulations for specific 
precautions to be taken.

6.0 Equipment and Supplies

    This procedure is not prescriptive on the type of equipment or 
the supplies necessary for the preparation of GMPS and GMACS gaseous 
cylinder standards, however SGM must use the appropriate equipment 
and supplies necessary to meet the uncertainty requirements in this 
appendix.

7.0 Reagents and Standards--Reserved

8.0 Procedures.

    The exact procedures used will depend on the gas manufacturer 
and the physical characteristics of the compound being prepared as a 
gaseous calibration standard. Any procedure is deemed appropriate so 
long as the criteria in section 8.1 for GMPS and section 8.2 for 
GMACS are met.
    8.1 Preparation and Certification of the GMPS.
    The GMPS certified value is established using the dual 
certification approach. A candidate GMPS cylinder is prepared 
gravimetrically, and its established reference value is confirmed by 
an independent measurement traceable to SI units as well as other 
appropriate reference materials. The level of agreement between the 
gravimetric reference value and the SI-based independent 
measurements along with the average value and associated, combined, 
expanded uncertainties serve to establish the certified reference 
value. If high purity reference material is not readily available 
for a gravimetric preparation, a user may petition the Administrator 
for an alternative method for preparation of a GMPS.
    The procedures for the gravimetric preparation, stability 
evaluation, and independent verification of GMPS must meet the 
criteria in this section following the procedures in 8.1(a) through 
(g).
    (a) Raw Materials
    (b) GMPS Cylinder Preparation/Creation
    (c) GMPS Cylinder Independent Verification
    (d) GMPS Cylinder Certification
    (e) GMPS Cylinder Stability
    (f) GMPS Cylinder Expiration Period
    (g) GMPS Documentation
    8.1.1 Raw Materials. Raw materials used in the production of 
GMPS must be of high quality (e.g., 99+% purity recommended). 
Additionally, because raw material purity is the largest component 
of uncertainty in gas gravimetry, SGMs must substantiate the purity 
of the raw material prior to use, either via (1) a validated 
certificate of analysis for the actual lot number purchased provided 
by the raw material vendor, or (2) a purity assay conducted by the 
SGM on the actual raw material to be used. The uncertainty of the 
raw material (Ur) assay must be included as one of the 
components of the total combined uncertainty for the mixture.
    8.1.2 GMPS Gravimetric Cylinder Preparation/Creation. The GMPS 
standards shall be based on a gravimetric preparation. The 
gravimetric preparation shall yield an expected concentration for 
the target component, and with the required statistical controls in 
place to calculate the uncertainty of that concentration.
    8.1.2.1 The scale used to generate the gravimetric reference 
standard must be independently calibrated over the range of target 
masses with ASTM E617-13 Class-1 weights on no less than a yearly 
basis. For such certifications, a high accuracy mass comparator 
(electronic or pendulum-type scale) is employed as the ``scale.'' 
The resolution of the scale should be sufficient to be able to 
calculate the overall uncertainty of any concentration derived from 
these steps.
    8.1.2.1.1 The scale used for the gravimetric operation must be 
independently calibrated and traceable to NIST standards with a 
defined uncertainty (ut).
    8.1.2.1.2 The scale calibration must be checked before the start 
of each new weighing operation (i.e., the day of) with a weight in 
the appropriate range that also meets ASTM E617-13 Class-1 
requirements.
    8.1.2.1.3 All material and equipment associated with the 
gravimetric analysis shall have or apply a procedure to estimate the 
uncertainty of the measurement, including but not limited to the 
balance(s) used (uca) standard weight (uw).
    8.1.2.1.4 The assay purity and associated material uncertainty 
(ur) of the assay for each component raw material and the 
balance gas must be known. This purity deviation is factored into 
the uncertainty of the mass of each material blended into the 
mixture.
    8.1.2.1.5 The procedures below are minimum requirements and do 
not speak to all of the details an SRM would do to ensure the 
preparation of a high-accuracy gravimetric candidate GMPS, (e.g., 
controls for external factors that would influence scale reading 
accuracy buoyancy effects, moisture/dust adsorption on the cylinder

[[Page 24164]]

surface, and errors caused by the location of the cylinder on the 
scale). The SGM should develop and follow and internal standard 
operation procedures (SOP) for the preparation of the candidate 
GMPS.
    8.1.2.1.6 Record the Target cylinder identification number, 
blend date, and balance gas on the appropriate form (see figure B-
1). Additionally, record the intended component(s) to be used in the 
preparation for this candidate GMPS, identifying the standard type, 
material name (e.g., Ethylene Oxide), MW (g/mol), and purity (wt%).
    8.1.2.1.7 Add the components to the candidate GMPS, recording 
the weight of each component added.
    8.1.2.1.8 GMPS Gravimetric Uncertainty. Calculate and document 
the gravimetric concentration (GMPS-Cg) for each 
component of the candidate GMPS. You must also document the combined 
uncertainty, expressed as the root sum of the uncertainty budget 
items identified, for the candidate GMPS value (GMPS-
Cgu). Gravimetric preparation uncertainty budget items 
include:
    (a) The purity of the raw material and the balance gas;
    (b) The measured accuracy of the (electronic) balance including 
consideration the uncertainty of the calibration weights, the 
calibration uncertainty, and its linearity;
    (c) The repeatability of the balance readings including errors 
caused by the location of the cylinder on the balance;
    (d) Balance Buoyancy effects;
    (e) Effects of moisture adsorption and dust on the outer surface 
of the cylinder;
    (f) Cylinder dilutions, if any, used to prepare target 
concentrations, including propagated uncertainties.
    8.1.3 GMPS Independent Verification. The certification of the 
candidate GMPS is based on independent measurements verifying the 
reference concentration of the gravimetrically prepared GMPS 
candidate. The independent verification must be based on a 
measurement approach traceable to the SI and may include the use of 
intrinsic NIST or accepted NMI reference materials to establish said 
traceability. Candidate independent verification measurement 
approaches include classical chemistry, spectroscopic approaches, as 
well as other instrumental approaches as long as adequate and 
appropriate SI traceability can be incorporated. The approach must 
be performed using NIST (or equivalent) traceable calibrations 
materials and using procedures that would allow the user to 
determine the overall uncertainty of the measurement. In some 
instances, a component may not be suitable to analysis using a 
classical approach, in those instances alternative approaches may be 
used do long as they (1) yield a concentration for the target com, 
(2) have a calculated uncertainty, (3) have traceability to the SI, 
and (4) documented conformity to the general metrological principles 
for primary methods outlined above.
    8.1.3.1 GMPS Independent Verification Measurement Uncertainty. 
The cumulative uncertainty of the GMPS independent verification 
measurement approach is integral to the ability to assess the 
overall quality of the independent verification measurement. You 
must also document the combined uncertainty, expressed as the root 
sum of the uncertainty budget items identified. Ensure that all 
known or suspected sources of bias and imprecision have been 
accounted for. The following elements are examples of sources of 
measurement error that must be included in the overall uncertainty 
calculation for the GMPS independent verification measurement:
    (a) The uncertainty of the certified reference solution (the 
traceability source);
    (b) Any propagated uncertainties through serial dilutions;
    (c) The errors in volumetric sampling of the candidate GMPS 
mixture;
    (d) The uncertainty of the instrument calibration curve (least 
squares fit and residual);
    (e) The bias or error associated with any measurement 
interferences;
    (f) The repeatability of replicate aliquot injections from the 
same sample;
    (g) The repeatability of replicate samples of the mixture;
    (h) Any external factors influencing sampling or instrument 
accuracy;
    (i) The uncertainty of measured volumetric gas flows;
    (j) The bias or uncertainty associated with quantitative gas 
flow delivery;
    (k) The error associated with instrumental measurement 
analyzers;
    (l) Replicate measurement instrument error and precision.
    8.1.4 GMPS Certification. The candidate GMPS certified value is 
based on three factors:
    (a) The relative agreement between the gravimetric reference 
value and the independent, measured value of the gravimetrically-
prepared GMPS candidate;
    (b) The combined, expanded uncertainty (k=2) of the gravimetric 
value and independently measured concentrations values;
    (c) The average of the independently measured concentrations 
values.
    8.1.4.1 GMPS Relative Agreement. Calculate the relative 
agreement according to equation B-1, expressed as Relative Percent 
Difference (RPD) between the gravimetric concentration (GMPS-
Cg) the independently measured concentrations (GMPS-
Ca). The results of these two analyses must agree within 
4.0 percent (%).
[GRAPHIC] [TIFF OMITTED] TR05AP24.020

    8.1.4.2 GMPS Combined, Expanded Uncertainty. Determine the 
individual uncertainties for the gravimetric approach (GMPS-
Cug) and the independent measurement verification 
approach (GMPS-Cua) according to equation B-2. Establish 
the GMPS combined, expanded uncertainty (GMPS-Cuc) as the 
root sum of the two individual uncertainties with a coverage factor 
k=2. The combined uncertainty must <=5.0 percent (%). If these 
objectives are not met, the candidate GMPS is not acceptable, and 
must not be used.
[GRAPHIC] [TIFF OMITTED] TR05AP24.021

    8.1.4.3 GMPS Certified Concentration Value. If the GMPS meets 
the Relative Agreement criteria in section 8.1.5.3 and the combined, 
expanded uncertainty criteria in section 8.1.5.4, the GMPS is valid. 
The GMPS certified value (GMPS-CC) is based on the 
independently measurement concentration (GMPS-Ca). The 
certification date is the date of the last confirmatory measurement.
    8.1.4.4 An SGMs may propose to Administrator an alternative 
acceptance values for section 8.1.5.1 or 8.1.5.2 for those 
components that are unable to meet the documented criteria. These 
proposals must include sufficient documentation that the objectives 
are unreasonable for a given component and concentrations.
    8.1.5 GMPS Stability Testing. The SGM must test and document 
mixture stability of the GMPS to assure that the mixture stays 
within claimed accuracy bounds for the entire claimed expiration 
period. Alternatively, once a preparation process has been 
developed, the SGM can perform a stability study consisting not less 
than three cylinders prepared using the defined process and at the 
concentration(s) defined by the process. Once the stability study 
cylinders have demonstrated acceptable stability for

[[Page 24165]]

the minimum expiration period (6-months), additional GMPS cylinders 
can be prepared under identical process conditions.
    8.1.5.1 The SGM may select the sampling frequency based on the 
targeted expiration period, the gas consumed in the analysis and 
expected component behavior. Stability testing data must consist of 
at least:
    (a) Five discrete samplings of the retained mixture for an 
expiration period of 6-months to 1-year;
    (b) Ten discrete samplings for an expiration period of 1-3 
years; and
    (c) Twenty for any period greater than 3 years.
    8.1.5.2 Stability testing must be conducted for each cylinder 
size/type and at a similar concentration as the candidate GMPS. 
Stability analyses must be performed using methods that assure 
consistent results can be achieved. If instrumental analysis using a 
gas standard is employed, use of a GMPS standard is highly 
recommended. In the absence of a certified GMPS, stability testing 
must be conducted using the same independent verification 
measurement procedures and methodology used in section 8.1.4, or 
using another known-to-be-stable gas standard containing the target 
component in a similar concentration range.
    8.1.5.3 Stability testing data must not show any upward or 
downward trends that would cause the mixture to become out of 
specification prior to the claimed expiration period.
    8.1.6 GMPS Expiration Period. The expiration period for the GMPS 
mixture based must be based on the empirical stability test data. 
The expiration periods for reactive gases must not exceed the length 
of the stability test, however for non-reactive gases you may 
forecast an expiration period not to exceed two times the actual 
stability testing duration. The maximum expiration period for a GMPS 
is time span from the date of preparation to the date of the last/
most recent stability study may not be less than 6-months. Provided 
that acceptable stability is observed, the maximum expiration period 
may be extended by retaining the stability study cylinders and 
performing additional analyses.
    8.1.7 GMPS Documentation. You must document the preparation of 
the GMPS through the appropriate record keeping and document the 
certification of a GMPS. The information is section 8.1.8.1 and 
8.1.8.2 must be maintained as a record by the SGM for the purpose of 
maintaining traceability and to verify the preparation. The 
information in section 8.1.8.3 must be documented and maintained by 
the SGM. This documentation and the records of the preparation and 
certification must be made available upon request by the appropriate 
delegated authority.
    8.1.7.1 The following information for the gravimetric 
preparation information of the GMPS must be documented and 
maintained as a record. This record should include but is not 
limited to the: blend date, gravimetric concentration, gravimetric 
concentration uncertainties as a percentage and absolute, reference 
material information and purity, scale ID, scale accuracy, and 
calculated gravimetric uncertainties associated with material, 
balance, and environmental effects. You must include sufficient 
information that will allow a 3rd party to recalculate the prepared 
concentration and expanded uncertainties.
    8.1.7.2 The following information for the analytical 
verification of the GMPS must be recorded and maintained as a 
record. This record should include the confirming methodology and 
any associated SOPs, confirming concentration(s), instrumentation 
used, calibration standards used and associated COAs, calibration 
curve data, replicate analysis calculated, and expanded 
uncertainties.
    8.1.7.3 The following information must be documented for 
inclusion on the COA for the GMACS.
    (a) Manufacturer's company name and address of the producing 
location
    (b) Manufacturer's part number for the GMPS, lot number, and/or 
production record.
    (c) Cylinder number, cylinder type, cylinder preparation ID, 
moisture dew point and cylinder pressure.
    (d) Certification date and claimed expiration date.
    (e) GMPS component(s) name, final certified concentration(s) 
(GMPS-Cc), and balance gas.
    (f) Gravimetric value and uncertainty
    (g)Verification value and uncertainty
    (h) GMPS final certified value and uncertainty absolute as a 
percentage (GMPS-Cu)
    8.2 Preparation and Certification of the GMACS. The preparation 
and certification of the candidate GMACS is also based on the 
independent verification of the gravimetrically prepared reference 
value. However, the independent verification utilizes the GMPS to 
perform the independent verification. This is accomplished by 
following the procedures in section 2.1 and 2.2 of the EPA 
Traceability Protocol, using the GMPS as the certified reference 
material. The measured value of the independent verification 
following the EPA Traceability Protocol procedures also establishes 
the certified reference value, providing the relative agreement 
performance criteria are met.
    8.2.1 GMACS Gravimetric Cylinder Preparation/Creation. The 
gravimetric preparation of the GMACS is identical to the procedures 
used to gravimetrically prepare the GMPS. You must maintain the same 
information required for the gravimetric preparation of GMPS, as 
found in section 8.1.8.1 for GMACS, as a record.
    8.2.2 GMACS Independent Verification and Certification. The 
candidate GMACS independent verification of the gravimetrically 
prepared reference value is contingent on the SGM following the 
procedures in sections 2.1 and 2.2 of the EPA Traceability Protocol. 
In addition, the EtO candidate GMACS certified reference value and 
associated expanded uncertainty is based on the EPA Traceability 
Protocol measured value. This is contingent upon the gravimetric and 
measured values meeting the relative agreement performance criteria 
established in section 8.1.5.3 and the uncertainty criteria 
established in section 8.1.5.4. Gas Manufacturers Intermediate 
Standards (GMIS) can be prepared by direct comparison to a GMPS that 
has been prepared and certified according to section 2.1.3.1 and 2.2 
of the EPA Traceability Protocol. The tagged value of the GMACS must 
be based on the EPA Traceability Protocol measured value as long as 
the performance criteria in sections 12.1 and 12.2 are met.
    8.2.3 GMACS Stability Testing. The SGM must test and document 
the stability of the GMACS to assure that the mixture stays within 
claimed certified bounds for the entire claimed expiration period. 
Use the procedures in section 8.1.6 to assess stability. The GMACS 
must also meet the requirements in section 2.1.5.2 of the EPA 
Traceability Protocol.
    8.2.4 GMACS Expiration Date. The certification period of the 
GMACS shall be based on the documented stability tests of the GMPS 
in section 8.1.6. The expiration date shall be based on the 
certification date, plus the certification period plus one day. 
There is not a maximum period of expiration; however, expiration 
periods must not be less than six months.
    8.2.5 GMACS Documentation You must document and maintain the 
same information required for the analytical verification of the 
GMPS, as found in section 8.1.8 for GMACS, as a record. The records 
of the preparation and certification must be made available upon 
request by the appropriate delegated authority.
    8.2.6 GMACS Certificate of Analysis (COA). You must provide 
comprehensive documentation of the GMPS and GMACS development 
process in the form of a GMACS Certificate of Analysis (COA) that 
accompanies each commercially distributed GMACS. As a minimum, the 
COA must contain the following information:
    (a) Identification of the gas as a Gas Manufacturer Alternative 
Certified Standard;
    (b) The cylinder number;
    (c) The certified concentration of the GMACS;
    (d) The combined expanded uncertainty (k=2) of the GMACS 
reference value (both absolute and relative);
    (e) The expiration date;
    (f) The reference materials or standards used (i.e., GMPS and 
GMIS);
    (g) The same information (cylinder number, certified 
concentration, uncertainties, expiration dates, etc. for these 
cylinders);
    (h) The gravimetric and independent measured verification 
reference concentration values and associated uncertainties for each 
GMPS used;
    (i) Associated measurement principles and uncertainties;
    (j) Any additional information stipulated by the EPA 
Traceability Protocol;
    (k) Any comments/special instructions.
    The SGM GMACS provider is encouraged to include additional 
relevant information to the COA, as appropriate. An example GMACS 
COA can be found in section 14 of this appendix.

9.0 Quality Control--Reserved

10.0 Calibration and Standardization

    There is a myriad of instrumental and mechanical techniques used 
in the

[[Page 24166]]

performance of this Appendix B. When reference methods are used, you 
must follow the calibration requirements of those methods and as 
defined in this appendix. For all other approaches, it is 
recommended to develop internal SOPs and develop.

11.0 Calculations and Data Analysis--Reserved

12.0 Method Performance

    12.1 GMPS/GMACS Relative Agreement. As part of the 
certification/verification procedures for the candidate GMPS and 
GMACS, the relative agreement between the gravimetrically prepared 
reference value and the independently measured verification value 
must agree within 4.0 percent (%).
    12.2 GMACS/GMPS Uncertainty. Final certification of the GMPS and 
GMACS reference concentrations must meet the combined expanded 
uncertainty (k=2) of <=5.0 percent (%).

13.0 Pollution Prevention--Reserved

14.0 Waste Management--Reserved

15.0 Bibliography

    1. EPA Traceability Protocol for Assay and Certification of 
Gaseous Calibration Standards, Office of Research and Development, 
National Risk Management Research Laboratory, May 2012, EPA 600/R-
12/531. https://www.epa.gov/air-research/epa-traceability-protocol-assay-and-certification-gaseous-calibration-standards.
    2. EPA Alternative Method 114, Approval of Alternative Method 
for preparation of HCl Gas Standards for PS-18 and Procedure 6, 
February 22, 2016, https://www.epa.gov/sites/default/files/2020-08/documents/alt114.pdf.
    3. Evaluation of Measurement Data--Guide to the Expression of 
Uncertainty in Measurement, JCGM 100:2008, https://www.bipm.org/documents/20126/2071204/JCGM_100_2008_E.pdf/cb0ef43f-baa5-11cf-3f85-4dcd86f77bd6.

16.0 Tables and Figures

Figure B-1 Example Gravimetric Preparation Sheet for GMPS and GMACS

BILLING CODE 6560-50-P
[GRAPHIC] [TIFF OMITTED] TR05AP24.022


[[Page 24167]]



Figure B-2 Apparatus for the assay of the GMACs
[GRAPHIC] [TIFF OMITTED] TR05AP24.023


[[Page 24168]]



Figure B-3 Examples COA
[GRAPHIC] [TIFF OMITTED] TR05AP24.024

BILLING CODE 6560-50-C

0
3. Appendix F to part 60 is amended by adding Procedure 7 to read as 
follows:

Appendix F to Part 60--Quality Assurance Procedures

* * * * *

Procedure 7. Quality Assurance Requirements for Gaseous Ethylene Exide 
(ETO) Continuous Emission Monitoring Systems Used for Compliance 
Determination

1.0 Applicability and Principle

    1.1 Applicability. Procedure 7 is used to evaluate the 
effectiveness of quality control (QC) and quality assurance (QA) 
procedures and to evaluate the quality of data produced by any 
ethylene oxide (EtO) gas, CAS: 75-21-8, continuous emission 
monitoring system (CEMS) that is used for determining compliance 
with emission standards for EtO on a continuous basis as specified 
in an applicable permit or regulation.
    1.1.1 This procedure specifies the minimum QA requirements 
necessary for the control and assessment of the quality of CEMS data 
submitted to the Environmental Protection Agency (EPA) or a 
delegated authority. If you are responsible for one or more CEMS 
used for EtO compliance monitoring you must meet these minimum 
requirements and you are encouraged to develop and implement a more 
extensive QA program or to continue such programs where they already 
exist.
    1.1.2 Data collected as a result of QA and quality control (QC) 
measures required in this procedure are to be submitted to the EPA 
or the delegated authority in accordance with the applicable 
regulation or permit. These data are to be used by both the 
delegated authority and you, as the CEMS operator, in assessing the 
effectiveness of the CEMS QC and QA procedures in the maintenance of 
acceptable CEMS operation and valid emission data.
    1.2 Principle
    1.2.1 The QA procedures consist of two distinct and equally 
important functions. One function is the assessment of the quality 
of the CEMS data by estimating accuracy. The other function is the 
control and improvement of the quality of the CEMS data by 
implementing QC policies and corrective actions. These two functions 
form an iterative control loop. When the assessment function 
indicates that the data quality is inadequate, the control effort 
must be increased until the data quality is acceptable. In order to 
provide uniformity in the assessment and reporting of data quality, 
this procedure specifies the assessment procedures to evaluate 
response drift and accuracy. The procedures specified are based on 
Performance Specification 19 (PS-19) in appendix B to this part.


[[Page 24169]]


    Note 1 to section 1.0:  Because the control and corrective 
action function encompasses a variety of policies, specifications, 
standards and corrective measures, this procedure treats QC 
requirements in general terms to allow you, as source owner or 
operator to develop the most effective and efficient QC system for 
your circumstances.

2.0 Definitions

    See PS-19 in appendix B to this part for the primary definitions 
used in this Procedure.

3.0 QC Requirements

    3.1 You, as a source owner or operator, must develop and 
implement a QC program. At a minimum, each QC program must include 
written procedures and/or manufacturer's information which should 
describe in detail, complete, step-by-step procedures and operations 
for each of the following activities:
    (a) Calibration Drift (CD) checks of CEMS;
    (b) CD determination and adjustment of CEMS;
    (c) Routine and preventative maintenance of CEMS (including 
spare parts inventory);
    (d) Data recording, calculations, and reporting;
    (e) Accuracy audit procedures for CEMS including reference 
method(s); and
    (f) Program of corrective action for malfunctioning CEMS.
    3.2 These written procedures must be kept on site and available 
for inspection by the delegated authority. As described in section 
5.4, whenever excessive inaccuracies occur for two consecutive 
quarters, you must revise the current written procedures, or modify 
or replace the CEMS to correct the deficiency causing the excessive 
inaccuracies.

4.0 Daily Data Quality Requirements and Measurement Standardization 
Procedures

    4.1 CD Assessment. An upscale gas, used to meet a requirement in 
this section must be a gas meeting the requirements in section 7.1 
of PS-19 of appendix B to this part.
    4.1.1 CD Requirement. Consistent with Sec.  60.13(d) and with 
Sec.  63.8(c) of this chapter, you, as source owners or operators of 
CEMS must check, record, and quantify the CD at two levels, using a 
zero gas and high-level gas at least once daily (approximately every 
24 hours). Perform the CD check in accordance with the procedure in 
the applicable performance specification (e.g., section 11.3 of PS-
19 in appendix B to this part). The daily zero- and high-level CD 
must not exceed two times the drift limits specified in the 
applicable performance specification (e.g., section 13.2 of PS-19 in 
appendix B to this part.)
    4.1.2 Recording Requirement for CD Corrective action. Corrective 
actions taken to bring a CEMS back in control after exceeding a CD 
limit must be recorded and reported with the associated CEMS data. 
Reporting of a corrective action must include the unadjusted 
concentration measured prior to resetting the calibration and the 
adjusted value after resetting the calibration to bring the CEMS 
back into control.
    4.1.3 Dynamic Spiking Option for high-level CD. You have the 
option to conduct a daily dynamic spiking procedure found in section 
11.5.8 of PS-19 of appendix B to this part in lieu of the daily 
high-level CD check. If this option is selected, the daily zero CD 
check is still required.
    4.1.4 Out of Control Criteria for Excessive CD. Consistent with 
Sec.  63.8(c)(7)(i)(A) of this chapter, an EtO CEMS is out of 
control if the zero or high-level CD exceeds two times the 
applicable CD specification in the applicable performance 
specification or in the relevant standard. When a CEMS is out of 
control, you as owner or operator of the affected source must take 
the necessary corrective actions and repeat the tests that caused 
the system to go out of control (in this case, the failed CD check) 
until the applicable performance requirements are met.
    4.1.5 Additional Quality Assurance for Data Above Span. This 
procedure must be used when required by an applicable regulation and 
may be used when significant data above span are being collected. 
Furthermore, the terms of this procedure do not apply to the extent 
that alternate terms are otherwise specified in an applicable rule 
or permit.
    4.1.5.1 Any time the average measured concentration of EtO 
exceeds 200 percent of the span value for two consecutive one-hour 
averages, conduct the following 'above span' CEMS response check.
    4.1.5.1.1 Within a period of 24 hours (before or after) of the 
'above span' period, introduce a higher, 'above span' EtO reference 
gas standard to the CEMS. Use 'above span' reference gas that meets 
the requirements of section 7.0 of PS-19 in appendix B to this part 
and target a concentration level between 75 and 125 percent of the 
highest hourly concentration measured during the period of 
measurements above span or 5 ppmv whichever is greater.
    4.1.5.1.2 Introduce the reference gas at the probe for 
extractive CEMS.
    4.1.5.1.3 At no time may the 'above span' concentration exceed 
the analyzer full-scale range.
    4.1.5.2 Record and report the results of this procedure as you 
would for a daily calibration. The 'above span' response check is 
successful if the value measured by the CEMS is within 20 percent of 
the certified value of the reference gas.
    4.1.5.3 If the 'above span' response check is conducted during 
the period when measured emissions are above span and there is a 
failure to collect at least one data point in an hour due to the 
response check duration, then determine the emissions average for 
that missed hour as the average of hourly averages for the hour 
preceding the missed hour and the hour following the missed hour.
    4.1.5.4 In the event that the 'above span' response check is not 
successful (i.e., the CEMS measured value is not within 20 percent 
of the certified value of the reference gas), then you must 
normalize the one-hour average stack gas values measured above the 
span during the 24-hour period preceding or following the 'above 
span' response check for reporting based on the CEMS response to the 
reference gas as shown in Eq. 7-1:
[GRAPHIC] [TIFF OMITTED] TR05AP24.025

    4.2 Out of Control Period Duration for Daily Assessments. The 
beginning of the out-of-control period is the hour in which the 
owner or operator conducts a daily performance check (e.g., 
calibration drift) that indicates an exceedance of the performance 
requirements established under this procedure. The end of the out-
of-control period is the completion of daily assessment of the same 
type following corrective actions, which shows that the applicable 
performance requirements have been met.
    4.3 CEMS Data Status During Out-of-Control Period. During the 
period the CEMS is out-of- control, the CEMS data may not be used in 
calculating compliance with an emissions limit nor be counted 
towards meeting minimum data availability as required and described 
in the applicable regulation or permit.

5.0 Data Accuracy Assessment

    You must audit your CEMS for the accuracy of EtO measurement on 
a regular basis at the frequency described in this section, unless 
otherwise specified in an applicable regulation or permit. Quarterly 
audits are performed at least once each calendar quarter. Successive 
quarterly audits, to the extent practicable, shall occur no closer 
than 2 months apart. Annual audits are performed at least once every 
four consecutive calendar quarters.
    5.1 Concentration Accuracy Auditing Requirements. Unless 
otherwise specified in an applicable regulation or permit, you must 
audit the EtO measurement accuracy of each CEMS at least once each 
calendar quarter, except in the case where the affected facility is 
off-line (does not operate). In that case, the audit must be 
performed as soon as is practicable in the quarter in which the unit 
recommences operation. Successive quarterly audits must, to the 
extent practicable, be performed no less than 2 months apart. The

[[Page 24170]]

accuracy audits shall be conducted as follows:
    5.1.1 Relative Accuracy Test Audit (RATA). A RATA must be 
conducted at least once every four calendar quarters, except as 
otherwise noted in sections 5.1.5 or 5.5 of this procedure. Perform 
the RATA as described in section 11.6 of PS-19 in appendix B to this 
part. If the EtO concentration measured by the RM during a RATA (in 
ppmv or other units of the standard) is less than or equal to 20 
percent of the concentration equivalent to the applicable emission 
standard, you must perform a Cylinder Gas Audit (CGA) or a Dynamic 
Spike Audit (DSA) for at least one subsequent (one of the following 
three) quarterly accuracy audits.
    5.1.2 Quarterly Relative Accuracy Audit (RAA). A quarterly RAA 
may be conducted as an option to conducting a RATA in three of four 
calendar quarters, but in no more than three quarters in succession. 
To conduct an RAA, follow the test procedures in section 11.6 of PS-
19 in appendix B to this part, except that only three test runs are 
required. The difference between the mean of the RM values and the 
mean of the CEMS responses relative to the mean of the values (or 
alternatively the emission standard) is used to assess the accuracy 
of the CEMS. Calculate the RAA results as described in section 6.2. 
As an alternative to an RAA, a cylinder gas audit or a dynamic 
spiking audit may be conducted.
    5.1.3 Cylinder Gas Audit. A quarterly CGA may be conducted as an 
option to conducting a RATA in three of four calendar quarters, but 
in no more than three consecutive quarters. To perform a CGA, 
challenge the CEMS with a zero-level and two upscale level audit 
gases of known concentrations within the following ranges:

------------------------------------------------------------------------
              Audit point                          Audit range
------------------------------------------------------------------------
1 (Mid-Level).........................  50 to 60% of span value.
2 (High-Level)........................  80 to 100% of span value.
------------------------------------------------------------------------

    5.1.3.1 Inject each of the three audit gases (zero and two 
upscale) three times each for a total of nine injections. Inject the 
gases so that the entire measurement system is challenged. Do not 
inject the same gas concentration twice in succession.
    5.1.3.2 Use EtO audit gases that meet the requirements of 
section 7 of PS-19 in appendix B to this part.
    5.2.3.3 Calculate results as described in section 6.3.
    5.1.4 Dynamic Spiking Audit. A quarterly DSA may be conducted as 
an option to conducting a RATA in three of four calendar quarters, 
but in no more than three quarters in succession.
    5.1.4.1 To conduct a DSA, you must challenge the entire EtO CEMS 
with a zero gas in accordance with the procedure in section 11.8 of 
PS-19 in appendix B of this part. You must also conduct the DS 
procedure as described in appendix A to PS-19 of appendix B to this 
part. You must conduct three spike injections with each of two 
upscale level audit gases. The upscale level gases must meet the 
requirements of section 7 of PS-19 in appendix B to this part and 
must be chosen to yield concentrations at the analyzer of 50 to 60 
percent of span and 80 to 100 percent of span. Do not inject the 
same spike gas concentration twice in succession.
    5.1.4.2 Calculate results as described in section 6.4. To 
determine CEMS accuracy, you must calculate the dynamic spiking 
error (DSE) for each of the two upscale audit gases using equation 
A5 in appendix A to PS-19 and equation 7-3 in section 6.4 of this 
Procedure.
    5.1.5 Other Alternative Quarterly Audits. Other alternative 
audit procedures, as approved by the Administrator, may be used for 
three of four calendar quarters.
    5.2 Out of Control Criteria for Excessive Audit Inaccuracy. If 
the results of the RATA, RAA, CGA, or DSA do not meet the applicable 
performance criteria in section 5.2.4, the CEMS is out-of-control. 
If the CEMS is out-of-control, take necessary corrective action to 
eliminate the problem. Following corrective action, the CEMS must 
pass a test of the same type that resulted in the out-of-control 
period to determine if the CEMS is operating within the 
specifications (e.g., a RATA must always follow an out-of-control 
period resulting from a RATA).
    5.2.1 If the audit results show the CEMS to be out-of-control, 
you must report both the results of the audit showing the CEMS to be 
out-of-control and the results of the audit following corrective 
action showing the CEMS to be operating within specifications.
    5.2.2 Out-Of-Control Period Duration for Excessive Audit 
Inaccuracy. The beginning of the out-of-control period is the time 
corresponding to the completion of the sampling for the failed RATA, 
RAA, CGA or DSA. The end of the out-of-control period is the time 
corresponding to the completion of the sampling of the subsequent 
successful audit.
    5.2.3 CEMS Data Status During Out-Of-Control Period. During the 
period the CEMS is out-of- control, the CEMS data may not be used in 
calculating emission compliance nor be counted towards meeting 
minimum data availability as required and described in the 
applicable regulation or permit.
    5.2.4 Criteria for Excessive Quarterly and Yearly Audit 
Inaccuracy. Unless specified otherwise in the applicable regulation 
or permit, the criteria for excessive inaccuracy are:
    5.2.4.1 For the RATA, the CEMS must meet the RA specifications 
in section 13.4 of PS-19 in appendix B to this part.
    5.2.4.2 For the CGA, the accuracy must not exceed 10.0 percent 
of the span value at the zero gas and the mid- and high-level 
reference gas concentrations.
    5.2.4.3 For the RAA, the RA must not exceed 20.0 percent of the 
RMavg as calculated using equation 7-2 in section 6.2 of this 
procedure whether calculated in units of EtO concentration or in 
units of the emission standard. In cases where the RA is calculated 
on a concentration (ppbv) basis, if the average EtO concentration 
measured by the RM during the test is less than 75 percent of the 
EtO concentration equivalent to the applicable standard, you may 
substitute the equivalent emission standard value (in ppbw) in the 
denominator of equation 7-2 in the place of RMavg and the 
result of this alternative calculation of RA must not exceed 15.0 
percent.
    5.2.4.4 For DSA, the accuracy must not exceed 5.0 percent of the 
span value at the zero gas and the mid- and high-level reference gas 
concentrations or 20.0 percent of the applicable emission standard, 
whichever is greater.
    5.3 Criteria for Acceptable QC Procedures. Repeated excessive 
inaccuracies (i.e., out-of-control conditions resulting from the 
quarterly or yearly audits) indicate that the QC procedures are 
inadequate or that the CEMS is incapable of providing quality data. 
Therefore, whenever excessive inaccuracies occur for two consecutive 
quarters, you must revise the QC procedures (see section 3.0) or 
modify or replace the CEMS.
    5.4 Criteria for Optional QA Test Frequency. If all the quality 
criteria are met in sections 4 and 5 of this procedure, the CEMS is 
in-control.
    5.5.1 Unless otherwise specified in an applicable rule or 
permit, if the CEMS is in-control and if your source emits <=75 
percent of the EtO emission limit for each averaging period as 
specified in the relevant standard for eight consecutive quarters 
that include a minimum of two RATAs, you may revise your auditing 
procedures to use CGA, RAA or DSA each quarter for seven subsequent 
quarters following a RATA.
    5.5.2 You must perform at least one RATA that meets the 
acceptance criteria every 2 years.
    5.5.3 If you fail a RATA, RAA, CGA, or DSA, then the audit 
schedule in section 5.2 must be followed until the audit results 
meet the criteria in section 5.3.4 to start requalifying for the 
optional QA test frequency in section 5.5.

6.0 Calculations for CEMS Data Accuracy

    6.1 RATA RA Calculation. Follow equations 9 through 14 in 
section 12 of PS-19 in appendix B to this part to calculate the RA 
for the RATA. The RATA must be calculated either in units of the 
applicable emission standard or in concentration units (ppbv).
    6.2 RAA Accuracy Calculation. Use equation 7-2 to calculate the 
accuracy for the RAA. The RA may be calculated in concentration 
units (ppmv) or in the units of the applicable emission standard.
[GRAPHIC] [TIFF OMITTED] TR05AP24.026


[[Page 24171]]


Where:

RA = Accuracy of the CEMS (percent)
MNavg = Average measured CEMS response during the audit 
in units of applicable standard or appropriate concentration.
RMavg = Average reference method value in units of 
applicable standard or appropriate concentration.

    6.3 CGA Accuracy Calculation. For each gas concentration, 
determine the average of the three CEMS responses and subtract the 
average response from the audit gas value. For extractive CEMS, 
calculate the ME at each gas level using equation 3A in section 12.3 
of PS-19 of appendix B to this part.
    6.4 DSA Accuracy Calculation. DSA accuracy is calculated as a 
percent of span. To calculate the DSA accuracy for each upscale 
spike concentration, first calculate the DSE using equation A5 in 
appendix A of PS-19 in appendix B to this part. Then use equation 7-
3 to calculate the average DSA accuracy for each upscale spike 
concentration. To calculate DSA accuracy at the zero level, use 
equation 3A in section 12.3 of PS-19 in appendix B to this part.
[GRAPHIC] [TIFF OMITTED] TR05AP24.027

7.0 Reporting Requirements

    At the reporting interval specified in the applicable regulation 
or permit, report for each CEMS the quarterly and annual accuracy 
audit results from section 6 and the daily assessment results from 
section 4. Unless otherwise specified in the applicable regulation 
or permit, include all data sheets, calculations, CEMS data records 
(i.e., charts, records of CEMS responses), reference gas 
certifications and reference method results necessary to confirm 
that the performance of the CEMS met the performance specifications.
    7.1 Unless otherwise specified in the applicable regulations or 
permit, report the daily assessments (CD and beam intensity) and 
accuracy audit information at the interval for emissions reporting 
required under the applicable regulations or permits.
    7.1.1 At a minimum, the daily assessments and accuracy audit 
information reporting must contain the following information:
    a. Company name and address.
    b. Identification and location of monitors in the CEMS.
    c. Manufacturer and model number of each monitor in the CEMS.
    d. Assessment of CEMS data accuracy and date of assessment as 
determined by a RATA, RAA, CGA or DSA described in section 5 
including:
    i. The RA for the RATA;
    ii. The accuracy for the CGA, RAA, or DSA;
    iii. The RM results, the reference gas certified values;
    iv. The CEMS responses;
    v. The calculation results as defined in section 6; and
    vi. Results from the performance audit samples described in 
section 5 and the applicable RMs.
    e. Summary of all out-of-control periods including corrective 
actions taken when CEMS was determined out-of-control, as described 
in sections 4 and 5. 7.1.2 If the accuracy audit results show the 
CEMS to be out-of-control, you must report both the audit results 
showing the CEMS to be out-of-control and the results of the audit 
following corrective action showing the CEMS to be operating within 
specifications.
    7.1.2 If the accuracy audit results show the CEMS to be out-of-
control, you must report both the audit results showing the CEMS to 
be out-of-control and the results of the audit following corrective 
action showing the CEMS to be operating within specifications.

8.0 Bibliography

1. EPA Traceability Protocol for Assay and Certification of Gaseous 
Calibration Standards, U.S. Environmental Protection Agency office 
of Research and Development, EPA/600/R-12/531, May 2012.
2. Method 205, ``Verification of Gas Dilution Systems for Field 
Instrument Calibrations,'' 40 CFR part 51, appendix M.

9.0 [Reserved]

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

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

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

Subpart A--General Provisions

0
5. Section 63.14 is amended by:
0
a. Revising paragraphs (a) and (f) and paragraph (i) introductory text;
0
b. Redesignating paragraphs (i)(88) through (119) as paragraphs (i)(89) 
through (120), and;
0
c. Adding new paragraph (i)(88) and note 2 to paragraph (i).
    The revisions and additions read as follows:


Sec.  63.14  Incorporations by reference.

    (a) Certain material is incorporated by reference into this part 
with the approval of the Director of the Federal Register under 5 
U.S.C. 552(a) and 1 CFR part 51. To enforce any edition other than that 
specified in this section, the EPA must publish a document in the 
Federal Register and the material must be available to the public. All 
approved incorporation by reference (IBR) material is available for 
inspection at the EPA and at the National Archives and Records 
Administration (NARA). Contact the EPA at: EPA Docket Center, Public 
Reading Room, EPA WJC West, Room 3334, 1301 Constitution Ave. NW, 
Washington, DC, telephone: 202-566-1744. For information on the 
availability of this material at NARA, visit www.archives.gov/federal-register/cfr/ibr-locations or email [email protected]. The 
material may be obtained from the sources in the following paragraphs 
of this section.
* * * * *
    (f) American Society of Mechanical Engineers (ASME), Two Park 
Avenue, New York, NY 10016-5990; phone: (800) 843-2763; email: 
[email protected]; website: www.asme.org.
    (1) ANSI/ASME PTC 19.10-1981, Flue and Exhaust Gas Analyses [Part 
10, Instruments and Apparatus], issued August 31, 1981; IBR approved 
for Sec. Sec.  63.309(k); 63.365(b); 63.457(k); 63.772(e) and (h); 
63.865(b); 63.997(e); 63.1282(d) and (g); 63.1625(b); table 5 to 
subpart EEEE; Sec. Sec.  63.3166(a); 63.3360(e); 63.3545(a); 
63.3555(a); 63.4166(a); 63.4362(a); 63.4766(a); 63.4965(a); 63.5160(d); 
table 4 to subpart UUUU; table 3 to subpart YYYY; Sec. Sec.  
63.7822(b); 63.7824(e); 63.7825(b); 63.8000(d); 63.9307(c); 63.9323(a); 
63.9621(b) and (c); 63.11148(e); 63.11155(e); 63.11162(f); 63.11163(g); 
63.11410(j); 63.11551(a); 63.11646(a); 63.11945; table 4 to subpart 
AAAAA; table 5 to subpart DDDDD; table 4 to subpart JJJJJ; table 4 to 
subpart KKKKK; table 4 to subpart SSSSS; tables 4 and 5 of subpart 
UUUUU; table 1 to subpart ZZZZZ; and table 4 to subpart JJJJJJ.
    (2) [Reserved]
* * * * *
    (i) ASTM International, 100 Barr Harbor Drive, P.O. Box CB700, West 
Conshohocken, Pennsylvania 19428-2959; phone: (800) 262-1373; website: 
www.astm.org.
* * * * *
    (88) ASTM D6348-12 (Reapproved 2020), Standard Test Method for 
Determination of Gaseous Compounds by Extractive Direct Interface 
Fourier Transform (FTIR) Spectroscopy,

[[Page 24172]]

Approved December 1, 2020; IBR approved for Sec.  63.365(b).
* * * * *

    Note 2 to paragraph (i):  Standards listed in this paragraph (i) 
may also be available from standards resellers including the 
Standards Store, https://global.ihs.com.

* * * * *

0
6. Subpart O is revised and republished to read as follows:

Subpart O--Ethylene Oxide Emissions Standards for Sterilization 
Facilities

Sec.
63.360 Applicability.
63.361 Definitions.
63.362 Standards.
63.363 Compliance and performance provisions.
63.364 Monitoring requirements.
63.365 Test methods and procedures.
63.366 Reporting requirements.
63.367 Recordkeeping requirements.
63.368 Implementation and enforcement.
Table 1 to Subpart O of Part 63 Standards for SCVs
Table 2 to Subpart O of Part 63 Standards for ARVs
Table 3 to Subpart O of Part 63 Standards for CEVs
Table 4 to Subpart O of Part 63 Standards for Group 1 Room Air 
Emissions
Table 5 to Subpart O of Part 63 Standards for Group 2 Room Air 
Emissions
Table 6 to Subpart O of Part 63 Applicability of General Provisions 
to Subpart O
Appendix A to Subpart O of Part 63--Monitoring Provisions for EtO 
CEMS

Subpart O--Ethylene Oxide Emissions Standards for Sterilization 
Facilities


Sec.  63.360  Applicability.

    (a) You are subject to the requirements of this subpart if you own 
or operate a sterilization facility that has an affected source 
specified in paragraph (b) of this section. Table 6 to this subpart 
shows which parts of the General Provisions in Sec. Sec.  63.1 through 
63.15 apply to you.
    (b) The affected sources subject to this subpart are:
    (1) Each SCV at any sterilization facility;
    (2) Each ARV at any sterilization facility;
    (3) Each CEV at any sterilization facility;
    (4) The collection of all Group 1 room air emissions at any 
sterilization facility; and
    (5) The collection of all Group 2 room air emissions at any 
sterilization facility.
    (c) An existing affected source is one the construction or 
reconstruction of which was commenced on or before April 13, 2023.
    (d) A new affected source is one the construction or reconstruction 
of which is commenced after April 13, 2023.
    (e) An SCV, ARV, or CEV is reconstructed if you meet the 
reconstruction criteria as defined in Sec.  63.2, and if you commence 
reconstruction after April 13, 2023.
    (f) This subpart does not apply to beehive fumigators.
    (g) This subpart does not apply to research or laboratory 
facilities as defined in section 112(c)(7) of title III of the Clean 
Air Act Amendment of 1990.
    (h) This subpart does not apply to EtO sterilization operations at 
stationary sources such as hospitals, doctor's offices, clinics, or 
other facilities whose primary purpose is to provide medical or dental 
services to humans or animals.
    (i) If you are an owner or operator of an area source subject to 
this subpart, you are exempt from the obligation to obtain a permit 
under 40 CFR part 70 or 71, provided you are not required to obtain a 
permit under 40 CFR 70.3(a) or 71.3(a) for a reason other than your 
status as an area source under this subpart. Notwithstanding the 
previous sentence, you must continue to comply with the provisions of 
this subpart applicable to area sources.
    (j) You must comply with the provisions of this subpart no later 
than the dates specified in paragraphs (j)(1) through (17) of this 
section:
    (1) If you own or operate an existing affected source, you must 
comply with the applicable provisions of this subpart no later than the 
dates specified in tables 1 through 5 to this subpart, as applicable.
    (2) If you own or operate a new affected source, and the initial 
startup of your affected source is on or before April 5, 2024, you must 
comply with the provisions of this subpart no later than April 5, 2024.
    (3) If you own or operate a new affected source, and the initial 
startup is after April 5, 2024, you must comply with the provisions of 
this subpart upon startup of your affected source.
    (4) If existing SCV, ARV, or CEV or parts of an existing collection 
of Group 1 or Group 2 room air emissions are replaced such that the 
replacement meets the definition of reconstruction in Sec.  63.2 and 
the reconstruction commenced after April 13, 2023, then the existing 
affected source becomes a new affected source. The reconstructed source 
must comply with the requirements for a new affected source upon 
initial startup of the reconstructed source or by April 5, 2024, 
whichever is later.
    (5) All existing SCVs at facilities that meet or exceed 1 tpy of 
EtO use within any consecutive 12-month period after April 7, 2025, 
that increase their EtO use after April 6, 2026, such that the SCV 
becomes subject to a more stringent emission standard, immediately upon 
becoming subject to the more stringent emission standard.
    (6) All existing SCVs at facilities that do not exceed 1 tpy of EtO 
use within any consecutive 12-month period after April 6, 2026, that 
increase their EtO use thereafter, such that the SCV becomes subject to 
a more stringent emission standard, immediately upon becoming subject 
to the more stringent emission standard.
    (7) All new SCVs at facilities that increase their EtO use over a 
year after startup such that the SCV becomes subject to a more 
stringent emission standard, immediately upon becoming subject to the 
more stringent emission standard.
    (8) All existing ARVs at facilities that meet or exceed 10 tpy of 
EtO use within any consecutive 12-month period after April 7, 2025, 
that increase their EtO use after April 6, 2026, such that the ARV 
becomes subject to a more stringent emission standard, immediately upon 
becoming subject to the more stringent emission standard.
    (9) All existing ARVs at facilities that do not exceed 10 tpy of 
EtO use within any consecutive 12-month period after April 6, 2026, 
that increase their EtO use after thereafter, such that the ARV becomes 
subject to a more stringent emission standard, immediately upon 
becoming subject to the more stringent emission standard.
    (10) All new ARVs at facilities that increase their EtO use over a 
year after startup such that the ARV becomes subject to a more 
stringent emission standard, immediately upon becoming subject to the 
more stringent emission standard.
    (11) All existing CEVs at facilities that do not exceed 60 tpy of 
EtO use within any consecutive 12-month period after April 6, 2026, 
that increase their EtO use thereafter, such that the CEV becomes 
subject to a more stringent emission standard, immediately upon 
becoming subject to the more stringent emission standard.
    (12) All new CEVs at facilities that increase their EtO use over a 
year after startup such that the CEV becomes subject to a more 
stringent emission standard, immediately upon becoming subject to the 
more stringent emission standard.
    (13) All existing collections of Group 1 room air emissions at 
facilities that do not exceed 40 tpy of EtO use within any consecutive 
12-month period after April 6, 2026, that increase their EtO use 
thereafter, such that the collection of Group 1 room air emissions 
becomes subject to a more stringent emission

[[Page 24173]]

standard, immediately upon becoming subject to the more stringent 
emission standard.
    (14) All new Group 1 room air emissions at facilities that increase 
their EtO use over a year after startup such that the Group 1 room air 
emissions become subject to a more stringent emission standard, 
immediately upon becoming subject to the more stringent emission 
standard.
    (15) All existing collections of Group 2 room air emissions at 
facilities that meet or exceed 4 tpy of EtO use within any consecutive 
12-month period after April 7, 2025, that increase their EtO use after 
April 6, 2026, such that the collection of Group 2 room air emissions 
becomes subject to a more stringent emission standard, immediately upon 
becoming subject to the more stringent emission standard.
    (16) All existing collections of Group 2 room air emissions at 
facilities that do not exceed 4 tpy of EtO use within any consecutive 
12-month period after April 6, 2026, that increase their EtO use 
thereafter, such that the collection of Group 2 room air emissions 
becomes subject to a more stringent emission standard, immediately upon 
becoming subject to the more stringent emission standard.
    (17) All new Group 2 room air emissions at facilities that increase 
their EtO use over a year after startup such that the Group 2 room air 
emissions become subject to a more stringent emission standard, 
immediately upon becoming subject to the more stringent emission 
standard.


Sec.  63.361  Definitions.

    Terms and nomenclature used in this subpart are defined in the 
Clean Air Act (the Act) as amended in 1990, Sec. Sec.  63.2 and 63.3, 
or in this section. For the purposes of this subpart, if the same term 
is defined in subpart A of this part and in this section, it shall have 
the meaning given in this section.
    Acid-water scrubber means an add-on air pollution control device 
that uses an aqueous or alkaline scrubbing liquor to absorb and 
neutralize acid gases.
    Aeration means, for the purposes of this rule, exposing sterilized 
material at elevated temperatures to drive EtO out of the material.
    Aeration room means any vessel or room that is used to facilitate 
off-gassing of EtO at a sterilization facility. If a facility uses only 
combination sterilization units, for the purposes of this rule, there 
are no aeration rooms at the facility.
    Aeration room vent (ARV) means the point(s) through which the 
evacuation of EtO-laden air from an aeration room occurs. For 
combination sterilization units, there is no ARV.
    Catalytic oxidizer means a combustion device that uses a solid-
phase catalyst to lower the temperature required to promote the 
oxidization and achieve adequate reduction of volatile organic 
compounds, as well as volatile hazardous air pollutants.
    Chamber exhaust vent (CEV) means the point(s) through which EtO-
laden air is removed from the sterilization chamber during chamber 
unloading following the completion of sterilization and associated air 
washes. This may also be referred to as a ``backvent'' (or ``back 
vent''). For combination sterilization units, there is no CEV.
    Combination sterilization unit means any enclosed vessel in which 
both sterilization and aeration of the same product occur within the 
same vessel, i.e., the vessel is filled with ethylene oxide gas or an 
ethylene oxide/inert gas mixture for the purpose of sterilizing and is 
followed by aeration of ethylene oxide.
    Combined emission stream means when the emissions from more than 
one emission source are routed together using common ductwork prior to 
the control system.
    Continuous monitoring system (CMS) means, for the purposes of this 
rule, the equipment necessary to continuously samples the regulated 
parameter specified in Sec.  63.364 or Sec.  63.365 of this subpart 
without interruption, evaluates the detector response at least once 
every 15 seconds, and computes and records the average value at least 
every 60 seconds, except during allowable periods of calibration and 
except as defined otherwise by the continuous emission monitoring 
system (CEMS) performance specifications (PS) in appendix B to part 60 
of this chapter.
    Control System Residence Time means the time elapsed from entrance 
of flow into the control system until gaseous materials exit the 
control system. For control systems with multiple exhaust streams 
whereby the residence time may vary for the streams, the residence time 
for purposes of complying with this subpart means the longest residence 
time for any exhaust stream in use. If a peak shaver is used, it is 
part of the control system, and its residence time must be considered.
    Deviation means any instance in which an owner or operator of an 
affected source, subject to this subpart:
    (1) Fails to meet any requirement or obligation established by this 
subpart including, but not limited to, any emission limitation, 
parameter value, or best management practice; or
    (2) Fails to meet any term or condition that is adopted to 
implement an applicable requirement in this subpart or that is included 
in the operating permit for any facility required to obtain such a 
permit.
    EtO dispensing means charging a sterilization chamber or chambers 
with EtO from non-cartridge storage media (e.g., drums, cylinders) via 
the use of piping, lines, and other equipment. This includes injection 
rooms and post-injection handling of containers.
    Gas/solid reactor means an add-on air pollution control device that 
uses a dry, solid-phase system to chemically convert EtO so that it 
becomes bound to the solid packing. This may also be referred to as a 
``dry bed reactor'' or a ``dry bed scrubber.''
    Group 1 room air emissions mean emissions from indoor EtO storage, 
EtO dispensing, vacuum pump operations, and pre-aeration handling of 
sterilized material.
    Group 2 room air emissions mean emissions from post-aeration 
handling of sterilized material.
    Indoor EtO storage means the storage of EtO within non-cartridge 
media (e.g., drums, cylinders) inside a sterilization building.
    Initial startup means the moment when an affected source subject to 
an emissions standard in Sec.  63.362 first begins operation.
    Injection room means any room where EtO is injected into containers 
(e.g., bags, pouches) that are filled with product to be sterilized.
    Maximum ethylene glycol concentration means the concentration of 
ethylene glycol in the scrubber liquor of an acid-water scrubber 
control device established during a performance test when the scrubber 
achieves the appropriate control of EtO emissions.
    Maximum gas/solid reactor pressure drop means the pressure drop of 
the gas/solid reactor established during a performance test when the 
gas/solid reactor achieves the appropriate control of EtO emissions.
    Maximum liquor tank level means the level of scrubber liquor in the 
acid-water scrubber liquor recirculation tank established during a 
performance test when the scrubber achieves the appropriate control of 
EtO emissions.
    Maximum scrubber liquor pH means the pH of the acid-water scrubber 
liquor established during a performance test when the scrubber achieves 
the appropriate control of EtO emissions.
    Minimum stack volumetric flow rate means the stack volumetric flow 
rate corrected established during a compliance demonstration when

[[Page 24174]]

permanent total enclosure (PTE) requirements are met.
    Minimum temperature at the inlet to the catalyst bed means the 
temperature at the inlet to the catalyst bed established during a 
performance test when the catalytic oxidizer achieves the appropriate 
control of EtO emissions.
    Minimum temperature difference across the catalyst bed means the 
temperature difference across the catalyst bed established during a 
performance test when the catalytic oxidizer achieves the appropriate 
control of EtO emissions.
    Minimum temperature in or immediately downstream of the firebox 
means the temperature in or immediately downstream of the firebox 
established during a performance test when the thermal oxidizer 
achieves the appropriate control of EtO emissions.
    Natural draft opening (NDO) means any permanent opening in the 
enclosure that remains open during operation of the facility and is not 
connected to a duct in which a fan is installed.
    Operating day means any day that a facility is engaged in a 
sterilization operation.
    Peak shaver means a device that is used to reduce high EtO 
concentrations within an exhaust stream such that the downstream 
control device is not overwhelmed.
    Permanent total enclosure (PTE) means a permanently installed 
enclosure that meets the criteria of Method 204 of appendix M, 40 CFR 
part 51 for a PTE. A PTE completely surrounds a source of emissions 
such that all EtO emissions are captured, contained, and directed to a 
control system or to an outlet(s).
    Post-aeration handling of sterilized material means the storage and 
transportation of material that has been removed from aeration but has 
not been placed in a vehicle for the sole purpose of distribution to 
another facility. Post-aeration handling of sterilized material ends 
when that vehicle is closed for the final time before leaving the 
facility. This definition does not include handling of material that 
has been both previously sterilized and not removed from aeration 
following re-sterilization.
    Post-injection handling of containers means the storage and 
transportation of containers (e.g., bags, pouches) that have been 
injected with EtO but have not been placed in a sterilization chamber.
    Pre-aeration handling of sterilized material means the storage and 
transportation of material that has been removed from a sterilization 
chamber but has not been placed in an aeration room. If only 
combination sterilization units are used, and if material is not moved 
out of the vessel between sterilization and aeration, then emissions 
from this source do not exist. This does not include post-injection 
handling of containers.
    Rolling sum means the weighted sum of all data, meeting QA/QC 
requirements or otherwise normalized, collected during the applicable 
rolling time period. The period of a rolling sum stipulates the 
frequency of data collection, summing, and reporting. As an example, to 
demonstrate compliance with a rolling 30-operating day sum emission 
reduction standard determined from hourly data, you must (1) determine 
the total mass of ethylene oxide prior to control and following control 
for each operating day; (2) then sum the current daily total mass prior 
to control with the previous 29 operating day total mass values and 
repeat the same process for the current daily total mass following 
control; and (3) then divide the 30-operating day total mass emissions 
following control by the 30-operating day total mass prior to control 
and subtract the resulting value from one to obtain the 30-operating 
day emission reduction achieved.
    Single-item sterilization means a process in which one or more 
items are placed in a pouch, EtO is injected into the pouch, and the 
sealed pouch is placed in a vessel to allow sterilization to occur.
    Sterilization chamber means any enclosed vessel or room that is 
filled with EtO gas, or an EtO/inert gas mixture, for the purpose of 
sterilizing and/or fumigating at a sterilization facility. This does 
not include injection rooms.
    Sterilization chamber vent (SCV) means the point (prior to the 
vacuum pump) through which the evacuation of EtO from the sterilization 
chamber occurs following sterilization or fumigation, including any 
subsequent air washes.
    Sterilization facility means any stationary source where EtO is 
used in the sterilization or fumigation of materials, including but not 
limited to facilities that engage in single-item sterilization.
    Sterilization operation means any time when EtO is removed from the 
sterilization chamber through the SCV or the chamber exhaust vent, when 
EtO is removed from the aeration room through the aeration room vent, 
when EtO is stored within the building, when EtO is dispensed from a 
container to a chamber, when material is moved from sterilization to 
aeration, or when materials are handled post-aeration.
    Thermal oxidizer means all combustion devices except flares.
    Vacuum pump operation means the operation of vacuum pumps, 
excluding dry seal vacuum pumps, for the purpose of removing EtO from a 
sterilization chamber.


Sec.  63.362  Standards.

    (a) Compliance date. If you own or operate an affected source, you 
must comply with the applicable requirement by the compliance date 
specified in Sec.  63.360(j). The standards of this section are 
summarized in tables 1 through 5 to this subpart.
    (b) Applicability of standards. The standards in paragraphs (c) 
through (k) of this section apply at all times. If using EtO CEMS to 
determine compliance with an applicable standard, this compliance 
demonstration is based on the previous 30-operating days of data. If 
using EtO CEMS to determine compliance with an applicable emission 
reduction standard in paragraphs (c) through (g) and (i) of this 
section for each operating day, you must determine the total inlet mass 
to and outlet mass from the control system using the procedures laid 
out in Sec.  63.364(f) and appendix A to this subpart, and you must 
maintain the emission limit based on the inlet mass and the applicable 
emission reduction standard. If using EtO CEMS to determine compliance 
with an applicable emission reduction standard in paragraph (j) of this 
section, you must continuously comply with the requirements of that 
paragraph.
    (c) SCV. You must comply with each applicable standard in table 1 
to this subpart, and you must meet each applicable requirement 
specified in Sec.  63.363. If a SCV is combined with a stream from 
another emission source, you must comply with the appropriate emission 
standard as prescribed in paragraph (i) of this section.
    (d) ARV. You must comply with each applicable standard in table 2 
to this subpart, and you must meet each applicable requirement 
specified in Sec.  63.363. If an ARV is combined with a stream from 
another emission source, you must comply with the appropriate emission 
standard as prescribed in paragraph (i) of this section.
    (e) CEV. You must comply with each applicable standard in table 3 
to this subpart, and you must meet each applicable requirement 
specified in Sec.  63.363. If a CEV is combined with a stream from 
another emission source, you must comply with the appropriate emission 
standard as prescribed in paragraph (i) of this section.
    (f) Group 1 room air emissions. You must comply with the applicable

[[Page 24175]]

standard in table 4 to this subpart, and you must meet each applicable 
requirement specified in Sec.  63.363. If Group 1 room air emissions 
are combined with a stream from another emission source, you must 
comply with the appropriate emission standard as prescribed in 
paragraph (i) of this section.
    (g) Group 2 room air emissions. You must comply with the applicable 
standard in table 5 to this subpart, and you must meet each applicable 
requirement specified in Sec.  63.363. If Group 2 room air emissions 
are combined with a stream from another emission source, you must 
comply with the appropriate emission standard as prescribed in 
paragraph (i) of this section. If you are required to limit the 
sterilization chamber concentration of EtO to 1 ppmv prior to opening 
the sterilization chamber door, you must meet the monitoring 
requirements specified in Sec.  63.364(h).
    (h) Capture systems. Room air emissions for which numerical limits 
are prescribed must be captured and routed under negative pressure to a 
control system. You may assume the capture system efficiency is 100 
percent if both conditions in paragraphs (h)(1) and (2) of this section 
are met:
    (1) The capture system meets the criteria in Method 204 of appendix 
M to 40 CFR part 51 for a PTE and directs all the exhaust gases from 
the enclosure to an add-on control system.
    (2) All sterilization operations creating exhaust gases for which 
the compliance demonstration is applicable are contained within the 
capture system.
    (i) Requirements for combined emission streams. When streams from 
two or more emission sources are combined, you must demonstrate 
compliance by either the approach specified in paragraph (i)(1) of this 
section or the approach specified in paragraph (i)(2) of this section 
in lieu of the applicable standards in paragraphs (c) through (g) of 
this section for the affected source. The combined emission stream 
limit is based on as 30-operating day rolling sum. In order to elect to 
comply with a combined emission streams limit, you must use a CEMS on 
each exhaust stack at the facility to determine compliance.
    (1) Monitoring after emission streams are combined. You must follow 
requirements of paragraphs (i)(1)(i) through (iii) of this section to 
determine the applicable combined emission streams limitation and 
demonstrate compliance. Under this approach, you must first determine 
the 30-operating day rolling sum of mass inlet to the control system. 
Then, the emission limitation is determined by applying the most 
stringent emission reduction standard to the 30-operating day rolling 
sum of the inlet mass. You must maintain actual emissions at or below 
that rate. For example, suppose a facility controls all of its ARVs and 
CEVs with one control system and that the emission reduction standards 
that apply to the ARVs and CEVs are 99.9% and 99%, respectively. 
Further suppose that the mass of uncontrolled EtO emissions from the 
combined stream is 5 lb during the 30-operating day period. Under this 
approach, the facility would need to apply an emission reduction of 
99.9% to the combined stream, resulting in an emission limit of 0.005 
lb for the 30-operating day period.
    (i) The combined emission streams limit for each 30-operating day 
period is determined daily by using equation 1 to this paragraph.
[GRAPHIC] [TIFF OMITTED] TR05AP24.028

Where:

CESCombined = The combined emission stream limit based 
upon monitoring after the emission streams are combined, in pounds.
M30day = The 30-operating day total mass sent to controls 
for the combined emission stream (i.e., monitoring data at the inlet 
of the control system), as calculated using equation A-3 and 
determined in accordance with appendix A to this subpart. The term 
``M30day'' as used in this equation is equivalent to the 
term ``E30day'' as designated in equation A-3.
Max(ER) = The most stringent emission reduction standard specified 
in tables 1 through 5 of this subpart applicable to any of the 
constituent streams, in decimal format.

    (ii) The 30-operating day rolling sum of emissions for the combined 
emission stream (i.e., monitoring data at the outlet of the control 
system) is calculated daily using equation A-3 and determined in 
accordance with appendix A to this subpart. For purposes of this 
section, this value is designated as ECombined. If the 
combined emission stream is split between two or more control systems, 
further sum the 30-operating day rolling sum of emissions from each 
control system to obtain ECombined.
    (iii) Compliance with the combined emission streams limitation 
shall be determined by demonstrating that ECombined, as 
calculated in accordance with paragraph (i)(1)(ii) of this section, for 
each 30-operating day period is at or below CESCombined, as 
calculated in paragraph (i)(1)(i) of this section.
    (2) Monitoring before emission streams are combined. You must 
follow requirements of paragraphs (i)(2)(i) through (iii) of this 
section to determine the applicable combined emission streams 
limitation and demonstrate compliance. Under this approach, you must 
first determine 30-operating day rolling sum of inlet mass to the 
control system for each component stream. Then, the emission limitation 
is determined by applying the applicable emission reduction standards 
to the 30-operating day rolling sum of each component stream and 
summing across the components. You must maintain actual emissions at or 
below that rate. For example, suppose a facility controls all of its 
ARVs and CEVs with one control system and that the emission reduction 
standards that apply to the ARVs and CEVs are 99.9% and 99%, 
respectively. Further suppose that during a 30-operating day period the 
mass of uncontrolled EtO emissions from the ARVs is 4 lb and the mass 
of uncontrolled EtO emissions from the CEVs is 1 lb. Under this 
approach, the facility would need to apply an emission reduction of 
99.9% to the ARV stream and an emission reduction of 99% to the CEV 
stream, resulting in an emission limit of 0.014 lb for the 30-operating 
day period.
    (i) The combined emission streams limit for each 30-operating day 
period is determined daily by using equation 2 to this paragraph.

[[Page 24176]]

[GRAPHIC] [TIFF OMITTED] TR05AP24.029

Where:

CESStreams = The combined emission stream limit based 
upon monitoring before the emission streams are combined, in pounds.
Mc,i = The 30-operating day total mass sent to controls 
for each non-SCV constituent emission stream (i.e., monitoring data 
at the inlet of the control system), as calculated using equation A-
3 and determined in accordance with appendix A to this subpart. The 
term ``Mc,i'' as used in this equation is equivalent to 
the term ``E30day'' as designated in equation A-3.
ERi = The applicable emission reduction standard from 
tables 2 through 5 of this subpart to each non-SCV constituent 
emission stream i.
i = Non-SCV constituent emission stream index.
n = Total number of non-SCV constituent emission streams.
Mc,j = The 30-operating day total mass sent to controls 
for each SCV emission stream, as determined in accordance with 
equation 10 of Sec.  63.364(f)(1)(i)(C)(1).
ERj = The applicable SCV emission reduction standard in 
table 1 to this subpart, in decimal format.
j = SCV emission stream index.
m = Total number of SCV emission streams.

    (ii) The 30-operating day rolling sum emissions for the combined 
emission stream (i.e., monitoring data at the outlet of the control 
system) is calculated daily using equation A-3 and determined in 
accordance with appendix A to this subpart. For purposes of this 
section, this value is designated as ECombined. If the 
combined emission stream is split between two or more control systems, 
then further sum the 30-operating day rolling sum emissions from each 
control system to obtain ECombined.
    (iii) Compliance with the combined emission streams limitation 
shall be determined by demonstrating that ECombined, as 
calculated in accordance with paragraph (i)(2)(ii) of this section, for 
each 30-operating day period is at or below CESStreams, as 
calculated paragraph (i)(2)(i) of this section.
    (3) If room air emissions are both subject to an emission standard 
and split between two or more control systems, then these control 
systems must be treated as part of the same control system.
    (j) Site-wide emission limitation. You may choose to comply with a 
site-wide emission limitation (SWEL) specified in this paragraph (j) in 
lieu of the applicable standards in paragraphs (c) through (g) of this 
section for the facility. The SWEL, which is calculated daily, is based 
on the previous 30 operating days of data. In order to elect to comply 
with a SWEL, you must utilize an EtO CEMS on each exhaust stack at the 
facility to determine compliance. The owner or operator may demonstrate 
compliance via one of the two SWEL approaches in lieu of the applicable 
standard(s) in paragraphs (c) through (g) of this section for the 
facility. If electing to comply with a SWEL, you must comply with 
paragraph (j)(3) of this section.
    (1) SWEL based upon facility EtO use. If you elect to comply with a 
SWEL based upon facility EtO use, you must follow requirements of 
paragraphs (j)(1)(i) through (iii) of this section to determine the 
applicable SWEL and demonstrate compliance. Under this approach, you 
first determine the 30-operating day rolling sum of EtO use. The SWEL 
is determined by multiplying by 0.99 and then applying the required SCV 
percent emission reduction standard in table 1 to this subpart to the 
30-operating day rolling sum of EtO usage. Then, for each CEMS at the 
outlet of the control systems at the facility, determine the 30-
operating day rolling sum of emissions. Finally, determine the facility 
actual emissions by summing the 30-operating day rolling sums for each 
CEMS at the facility. You must maintain actual emissions at or below 
the SWEL.
    (i) The SWEL for each 30-operating day period is determined daily 
by using equation 3 to this paragraph.
[GRAPHIC] [TIFF OMITTED] TR05AP24.030

Where:

SWELFac = SWEL based upon facility EtO use, in pounds.
MFac = Facility EtO use over the previous 30 operating 
days, in pounds, as determined in accordance with equation 11 of 
Sec.  63.364(i)(2).
0.99 = Adjustment factor for EtO residual in sterilized product.
ERSCV = The applicable SCV emission reduction standard in 
table 1 to this subpart, in decimal format.

    (ii) The 30-operating day rolling sum of emissions are determined 
daily using equation 4 to this paragraph.
[GRAPHIC] [TIFF OMITTED] TR05AP24.031

Where:

EFac = The total emissions from the facility over the 
previous 30-operating days, in pounds.
Eo,i = The 30-operating day rolling sum of emissions 
calculated at each exhaust stack, i, monitored by an EtO CEMS, as 
calculated using equation A-3 of appendix A to this subpart.
i = Exhaust stack index
n = Total number of exhaust stacks

    (iii) Compliance with the SWEL based upon facility EtO usage shall 
be

[[Page 24177]]

determined by demonstrating that EFac, as calculated in 
accordance with paragraph (j)(1)(ii) of this section, for each 30-
operating day period is at or below the SWEL, as calculated paragraph 
(j)(1)(i) of this section.
    (2) SWEL based upon emissions streams. If you elect to comply with 
a SWEL based upon emissions streams, you must follow requirements of 
paragraphs (j)(2)(i) through (iii) of this section to determine the 
applicable SWEL and demonstrate compliance. Under this approach, for 
each non-SCV affected source, you must determine the mass of EtO sent 
to controls and apply the applicable emission reduction standard. For 
each SCV affected source, you must determine the mass of EtO sent to 
controls as specified in Sec.  63.364(f)(1)(i)(C)(1) and apply the 
applicable emission reduction standard. The SWEL is determined by 
summing across the result of this calculation for each affected source 
(both non-SCV and SCV). Then, for each CEMS at the outlet of the 
control system(s) at the facility, determine the 30-operating day 
rolling sum of emissions. Finally, determine the facility actual 
emissions by summing the 30-operating day rolling sums for each CEMS at 
the facility. You must maintain actual emissions at or below the SWEL.
    (i) The SWEL for each 30-operating day period is determined daily 
by using equation 5 to this paragraph.
[GRAPHIC] [TIFF OMITTED] TR05AP24.032

Where:

SWELStreams = SWEL based upon individual emissions 
streams, in pounds.
Mc,i = The 30-operating day total mass sent to controls 
(i.e., monitoring data at the inlet of the control system) for each 
non-SCV emission stream, as calculated using equation A-3 and 
determined in accordance with appendix A to this subpart. The term 
``Mc,i'' as used in this equation is equivalent to the 
term ``E30day'' as designated in equation A-3.
ERi = The applicable emission reduction standard to each 
non-SCV emission stream, i, specified in tables 1 through 5 of this 
subpart, in decimal format.
i = Non-SCV emission streams index.
n = Total number of non-SCV emission streams.
Mc,j = The 30-operating day total mass sent to controls 
for each SCV emission stream, as determined in accordance with 
equation 10 in Sec.  63.364(f)(1)(i)(C)(1).
ERj = The applicable SCV emission reduction standard in 
table 1 to this subpart, in decimal format.
j = SCV emission stream index.
m = Total number of SCV emission streams.

    (ii) The 30-operating day rolling sum of emissions are determined 
daily using equation 4 to this section.
    (iii) Compliance with the SWEL based upon emission streams shall be 
determined by demonstrating that EFac, as calculated in 
accordance with paragraph (j)(2)(ii) of this section, for each 30-
operating day period is at or below SWELStreams, as 
calculated in paragraph (j)(2)(i) of this section.
    (3) Boundary. The boundary for this approach includes all affected 
sources at the facility.
    (k) General duty. At all times, you must operate and maintain any 
affected source, including associated air pollution control equipment 
and monitoring equipment, in a manner consistent with safety and good 
air pollution control practices for minimizing emissions. The general 
duty to minimize emissions does not require the owner or operator to 
make any further efforts to reduce emissions if levels required by the 
applicable standard have been achieved. Determination of whether a 
source is operating in compliance with operation and maintenance 
requirements will be based on information available to the 
Administrator which may include, but is not limited to, monitoring 
results, review of operation and maintenance procedures, review of 
operation and maintenance records, and inspection of the source.


Sec.  63.363  Compliance and performance provisions.

    (a) Continuous compliance. You must demonstrate continuous 
compliance with the applicable emission standard(s) using an EtO CEMS, 
including a shared EtO CEMS, installed and operated in accordance with 
the requirements of Performance Specification 19 in appendix B and 
Procedure 7 in appendix F to part 60 of this chapter. Alternatively, if 
you own or operate a facility where EtO use is less than 100 pounds/yr, 
you may demonstrate continuous compliance by conducting annual 
performance tests using the performance testing requirements in Sec.  
63.7, according to the applicability in table 6 to this subpart, the 
procedures listed in this section, and the test methods listed in Sec.  
63.365. If you elect to demonstrate compliance through periodic 
performance testing, you must also demonstrate continuous compliance 
with each operating limit required under this section according to the 
methods specified in Sec.  63.364. If you own or operate an area source 
facility where EtO use is less than 100 pounds/yr where an existing 
collection of Group 2 room air emission is operated in accordance with 
the PTE requirements of EPA Method 204 of appendix M to part 51 of this 
chapter, you may instead conduct these performance tests once every 
three years.
    (b) Initial compliance for Facilities that use EtO CEMS. To 
demonstrate initial compliance with an emission standard using a CEMS 
that measures HAP concentrations directly (i.e., an EtO CEMS), the 
initial performance test must consist of the first 30 operating days 
after the certification of the CEMS according to Performance 
Specification 19 in Appendix B to part 40 of this chapter. The initial 
compliance demonstration period must be completed on or before the date 
that compliance must be demonstrated (i.e., 180 days after the 
applicable compliance date). You must follow the procedures in appendix 
A to this subpart.
    (1) The CEMS performance test must demonstrate compliance with the 
applicable EtO standards in tables 1 through 5 to this subpart. 
Alternatively, the CEMS performance test may demonstrate compliance 
with Sec.  63.362(i) or (j).
    (i) You may time-share your CEMS among different measurement points 
provided that:
    (A) The measurement points are approximately equidistant from the 
CEMS;
    (B) The sampling time at each measurement point is at least 3 times 
as long as the CEMS response time;
    (C) The CEMS completes at least one complete cycle of operation for 
each shared measurement point within a 15-minute period; and

[[Page 24178]]

    (D) The CEMS meets the other requirements of PS 19.
    (2) You must collect hourly data from auxiliary monitoring systems 
during the performance test period, to convert the pollutant 
concentrations to pounds per hour.
    (c) Initial compliance demonstration where facility EtO use is less 
than 100 pounds per year. If you own or operate an affected source that 
is both subject to an emission standard in Sec.  63.362 and located 
within a facility where EtO use is less than 100 pounds per year, you 
may comply with paragraphs (c)(1) and (2) of this section:
    (1) Conduct an initial compliance demonstration using the 
procedures listed in Sec.  63.7 of this part according to the 
applicability in table 6 to this subpart, the procedures listed in this 
section, and the test methods listed in Sec.  63.365;
    (2) Complete the initial compliance demonstration within 180 days 
after the compliance date for the affected source as determined in 
Sec.  63.360(j).
    (d) Operating limits for facility where EtO use is less than 100 
lb/yr. If annual EtO use at the facility is less than 100 lb, the 
procedures in paragraphs (d)(1) through (5) of this section may be used 
to determine compliance with the standard(s) under Sec.  63.362(c) 
through (g) and to establish operating limits for each of the control 
devices, as applicable:
    (1) You must determine the percent emission reduction of the 
control system used to comply with Sec.  63.362(c) through (g) using 
the test methods and procedures in Sec.  63.365(d)(1).
    (2) If an acid-water scrubber(s) is used to comply with a standard, 
then you must establish as an operating limit:
    (i) The maximum ethylene glycol concentration using the procedures 
described in Sec.  63.365(e)(1)(i);
    (ii) The maximum liquor tank level using the procedures described 
in Sec.  63.365(e)(1)(ii); or
    (iii) The maximum scrubber liquor pH using the procedures described 
in Sec.  63.365(e)(1)(iii).
    (3) If a thermal oxidizer(s) is used to comply with a standard, you 
must establish as an operating limit the minimum temperature in or 
immediately downstream of the firebox using the procedures described in 
Sec.  63.365(e)(2).
    (4) If a catalytic oxidizer(s) is used to comply with the standard, 
you must establish as operating limits both:
    (i) The minimum temperature at the inlet to the catalyst bed using 
the procedures described in Sec.  63.365(e)(3); and
    (ii) The minimum temperature difference across the catalyst bed 
using the procedures described in Sec.  63.365(e)(3).
    (5) If a gas/solid reactor(s) is used to comply with the standard, 
you must establish as an operating limit the pressure drop across the 
media beds and conduct weekly sampling and analysis of the media. 
Determine the maximum gas/solid reactor pressure drop using the 
procedures described in Sec.  63.365(e)(4).
    (e) Other control technology for facility where EtO use is less 
than 100 lb/yr. If you are conducting a performance test using a 
control technology other than an acid-water scrubber, catalytic 
oxidizer, thermal oxidizer, or gas/solid reactor, you must provide to 
the Administrator information describing the design and operation of 
the air pollution control system, including recommendations for the 
parameters to be monitored that will demonstrate continuous compliance. 
Based on this information, the Administrator will determine the 
parameter(s) to be measured during the performance test. During the 
performance test required in paragraph (a) of this section, using the 
methods approved in Sec.  63.365(e)(5), you must determine the site-
specific operating limit(s) for the operating parameters approved by 
the Administrator. You must submit the information at least sixty days 
before the performance test is scheduled to begin. The information on 
the control technology must include the five items listed in paragraphs 
(1) through (5) of this section:
    (1) Identification of the specific parameters you propose to use as 
additional operating limits;
    (2) A discussion of the relationship between these parameters and 
emissions of regulated pollutants, identifying how emissions of 
regulated pollutants change with changes in these parameters and how 
limits on these parameters will serve to limit emissions of regulated 
pollutants;
    (3) A discussion of how you will establish the upper and/or lower 
values which will establish the operating limits for these parameters;
    (4) A discussion identifying the methods you will use to measure 
and the instruments you will use to monitor these parameters, as well 
as the relative accuracy and precision of these methods and 
instruments; and
    (5) A discussion identifying the frequency and methods for 
recalibrating the instruments you will use for monitoring these 
parameters.
    (f) Other emission streams. If the emission stream does not consist 
only of an SCV(s), the procedures in paragraphs (f)(1) through (3) of 
this section shall be used to determine initial compliance with the 
emission limits under Sec.  63.362(d) through (g), as applicable:
    (1) You must comply with paragraph (c) of this section, as 
applicable.
    (2) If you are complying with a percent emission reduction standard 
as specified in tables 1 through 5 to this subpart, you must determine 
compliance with Sec.  63.362(c) through (g), as applicable, using the 
test methods and procedures in Sec.  63.365(d)(1).
    (3) If you are required to operate any portion of the facility 
under PTE, you must initially demonstrate that the PTE meets the 
requirements of Method 204 of 40 CFR part 51, appendix M, and that all 
exhaust gases from the enclosure are delivered to a control system or 
stack(s). You must also meet the requirements in Sec.  63.363(f)(3)(i) 
and either Sec.  63.363(f)(3)(ii) or (iii):
    (i) Maintain direction of the airflow into the enclosure at all 
times, verifying daily using the procedures described in Sec.  
63.364(f)(5) and meet either of the requirements.
    (ii) Establish as an operating limit the minimum volumetric flow 
rate through the affected stack(s) using the procedures described in 
Sec.  63.365(f)(1); or
    (iii) Install, operate, calibrate, and maintain a continuous 
pressure differential monitoring system using the procedures described 
in Sec.  63.364(f)(4).


Sec.  63.364  Monitoring requirements.

    (a) General requirements. (1) If you own or operate an affected 
source subject to an emission standard in Sec.  63.362, you must comply 
with the monitoring requirements in Sec.  63.8, according to the 
applicability in table 6 to this subpart, and in this section.
    (2) If you own or operate an affected source at a facility where 
EtO use is less than 100 lb/yr that is subject to an emission standard 
in Sec.  63.362, you may monitor the parameters specified in paragraphs 
(b), (c), (d), (e), (g), and (i) of this section. All monitoring 
equipment shall be installed such that representative measurements of 
emissions or process parameters from the source are obtained. For 
monitoring equipment purchased from a vendor, verification of the 
operational status of the monitoring equipment shall include completion 
of the manufacturer's written specifications or recommendations for 
installation, operation, and calibration of the system.
    (3) If you own or operate an affected source that is subject to an 
emission standard in Sec.  63.362 and that is required to monitor using 
EtO CEMS, you must

[[Page 24179]]

comply with paragraphs (f), (g), and (i) of this section.
    (4) If you comply with the management practice for Group 2 room air 
emissions at area sources, you must comply with paragraph (h) of this 
section.
    (5) You must keep the written procedures required by Sec.  
63.8(d)(2) on record for the life of the affected source or until the 
affected source is no longer subject to the provisions of this part, to 
be made available for inspection, upon request, by the Administrator. 
If the performance evaluation plan is revised, you must keep previous 
(i.e., superseded) versions of the performance evaluation plan on 
record to be made available for inspection, upon request, by the 
Administrator, for a period of 5 years after each revision to the plan. 
The program of corrective action should be included in the plan 
required under Sec.  63.8(d)(2).
    (b) Acid-water scrubbers. If you are demonstrating continuous 
compliance through periodic performance testing on an acid-water 
scrubber(s), you must:
    (1) Ethylene glycol concentration. Sample the scrubber liquor from 
the acid-water scrubber(s) and analyze and record at least once per 
week the ethylene glycol concentration of the scrubber liquor using the 
test methods and procedures in Sec.  63.365(e)(1). Monitoring is 
required during a week only if the scrubber unit has been operated. You 
must maintain the weekly ethylene glycol concentration below the 
operating limit established during the most recent performance test;
    (2) Scrubber liquor tank level. Measure and record at least once 
per day the level of the scrubber liquor in the recirculation tank(s). 
You must install, maintain, and use a liquid level indicator to measure 
the scrubber liquor tank level (i.e., a marker on the tank wall, a 
dipstick, a magnetic indicator, etc.). Monitoring is required during a 
day only if the scrubber unit has been operated. You must maintain the 
daily scrubber liquor height in each recirculation tank below the 
applicable operating limit established during the most recent 
performance test; or
    (3) pH. Monitor and record at least every 15 minutes the scrubber 
liquor pH. Monitoring is required when the scrubber is operating. A 
data acquisition system for the pH monitor shall compute and record 
each 3-hour average scrubber liquor pH value, rolled hourly. This must 
be done by first averaging the scrubber liquor pH readings obtained 
over a clock hour, i.e., beginning and ending on the hour. All data 
collected during the operating hour must be used, even if the scrubber 
unit is not operating for a complete hour. Then, the average of the 
previous 3 operating hours must be calculated to determine the 3-hour 
rolling average scrubber liquor pH. You must maintain the 3-hour 
rolling average scrubber liquor pH below the applicable operating limit 
established during the most recent performance test. You must ensure 
the pH monitoring system meets the following requirements:
    (i) The pH sensor must be installed in a position that provides a 
representative measurement of scrubber liquor pH;
    (ii) The sample must be properly mixed and representative of the 
fluid to be measured; and
    (iii) 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 must be conducted in 
accordance with your monitoring plan at the time of each performance 
test but no less frequently than quarterly.
    (c) Oxidizers. If you are demonstrating continuous compliance 
through periodic performance testing on a catalytic oxidizer or thermal 
oxidizer, the requirements in paragraphs (c)(1) and (2) of this section 
apply:
    (1) For thermal oxidizers, you must monitor and record at least 
every 15 minutes the temperature in or immediately downstream of the 
firebox using the temperature monitor described in paragraph (c)(4) of 
this section. Monitoring is required when the thermal oxidizer is 
operating. A data acquisition system for the temperature monitor shall 
compute and record each 3-hour average temperature value, rolled 
hourly. This must be done by first averaging the temperature readings 
over a clock hour, i.e., beginning and ending on the hour. All data 
collected during the operating hour must be used, even if the thermal 
oxidizer is not operating for a complete hour. Then, the average of the 
previous 3 operating hours must be calculated to determine the 3-hour 
rolling average temperature in or immediately downstream of the 
firebox. You must maintain the 3-hour rolling average temperature above 
the operating limit established during the most recent performance 
test.
    (2) For catalytic oxidizers, you must monitor and record at least 
every 15 minutes the temperature at the inlet to the catalyst bed using 
the temperature monitor described in paragraph (c)(4) of this section. 
Monitoring is required when the catalytic oxidizer is operating. A data 
acquisition system for the temperature monitor shall compute and record 
each 3-hour average temperature, rolled hourly. This must be done by 
first averaging the temperature readings over a clock hour, i.e., 
beginning and ending on the hour. All data collected during the 
operating hour must be used, even if the catalytic oxidizer is not 
operating for a complete hour. Then, the average of the previous 3 
operating hours must be calculated to determine the 3-hour rolling 
average temperature at the inlet to the catalyst bed. You must maintain 
the 3-hour rolling average temperature above the operating limit 
established during the most recent performance test.
    (3) For catalytic oxidizers, you must monitor and record at least 
every 15 minutes the temperature increase across the catalyst bed, 
immediately downstream of the catalytic bed, using the temperature 
monitor described in paragraph (c)(4) of this section. Monitoring is 
required when the catalytic oxidizer is operating. A data acquisition 
system for the temperature monitor shall compute and record each 3-hour 
average temperature increase, rolled hourly. This must be done by first 
computing the difference in outlet temperature minus inlet temperature 
(monitored under paragraph (c)(2)), and second averaging the 
temperature difference values over a clock hour, i.e., beginning and 
ending on the hour. All data collected during the operating hour must 
be used, even if the catalytic oxidizer is not operating for a complete 
hour. Then, the average of the previous 3 operating hours must be 
calculated to determine the 3-hour rolling average temperature increase 
across the catalyst bed. You must maintain the 3-hour average 
temperature increase above the operating limit established during the 
most recent performance test.
    (4) You must 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. You must verify 
the accuracy of the temperature monitor twice each calendar year at 
least five months apart 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).
    (5) For catalytic oxidizers, if the monitor indicates that the 
temperature is below the operating limit, within 7 calendar days you 
must:

[[Page 24180]]

    (i) Correct the temperature or temperature increase so that it 
falls within the established operating range; or
    (ii) Replace the catalyst bed. Following replacement of the 
catalyst bed, you must conduct a new performance test within 180 days 
and re-establish the operating limits.
    (d) Gas-solid reactors. If you are demonstrating continuous 
compliance through periodic performance testing on a gas/solid 
reactor(s), you must:
    (1) Media analysis. Sample the media from the gas/solid reactor(s) 
and have the manufacturer analyze at least once per week. Monitoring is 
required during a week only if the gas/solid reactor unit has been 
operated; and
    (2) Pressure drop. Monitor and record at least every 15 minutes the 
pressure drop. Monitoring is required when the gas/solid reactor is 
operating. A data acquisition system for the pressure drop monitor 
shall compute and record each 3-hour average gas/solid reactor pressure 
drop value, rolled hourly. This must be done by first averaging the 
gas/solid reactor pressure drop readings obtained over a clock hour, 
i.e., beginning and ending on the hour. All data collected during the 
operating hour must be used, even if the gas/solid reactor unit is not 
operating for a complete hour. Then, the average of the previous 3 
operating hours must be calculated to determine the 3-hour rolling 
average gas/solid reactor pressure drop. You must maintain the 3-hour 
rolling average gas/solid reactor pressure drop below the applicable 
operating limit established during the most recent performance test.
    (e) Performance testing, other control technology. If you are 
complying with Sec.  63.363(d) or (e) using periodic performance 
testing and the use of a control device other than acid-water 
scrubbers, catalytic or thermal oxidizers, or gas/solid reactors, you 
must monitor the parameters as approved by the Administrator using the 
methods and procedures in Sec.  63.365(e).
    (f) EtO CEMS configurations. If you are using EtO CEMS to 
demonstrate compliance with an emission standard, you must install and 
operate an EtO CEMS on each outlet for the control system in accordance 
with the requirements of Appendix A to subpart O of this part. You must 
also conduct monitoring for each inlet to the control system that is 
used to demonstrate compliance with the emission reduction standard in 
accordance with the requirements of appendix A to this subpart, with 
the exception for SCV emission streams to the control system.
    (1) EtO CEMS inlet configuration. The following caveats apply:
    (i) SCVs. If you do not own or operate a single-item sterilizer, to 
demonstrate compliance with the percent emission reduction standards 
for emissions streams that are comprised only of SCVs, you may use the 
following procedures as an alternative to monitoring the inlet emission 
stream to determine the mass emissions of EtO being emitted via 
sterilization chamber(s) vents prior to the controls.
    (A) Determine the mass (MSCV,n) of EtO used for each 
charge and at each sterilization chamber used during the previous 30 
days using the procedures in either paragraph (f)(1)(i)(A)(1) or (2) of 
this section.
    (1) Weigh the EtO gas cylinder(s) used to charge the sterilizer(s) 
before and after charging. Record these weights to the nearest 45 g 
(0.1 lb) and calculate the theoretical mass (Mc) vented to 
the controls using equation 1 to this paragraph.
[GRAPHIC] [TIFF OMITTED] TR05AP24.033


Where:

MSCV,n = Theoretical total mass of EtO vented to controls 
per charge, g (lb)
Mcharge = total mass of sterilizer gas charge, g (lb)
%EOw = weight percent of EtO

    (2) Install a calibrated rate meter at the sterilizer inlet(s) and 
continuously measure the flow rate (Qm) and duration of each 
sterilizer charge. Calculate the theoretical mass (MSCV,n) 
vented to the controls using equation 2 to this paragraph.
[GRAPHIC] [TIFF OMITTED] TR05AP24.034


Where:

MSCV,n = theoretical total mass of EtO sent to controls 
per charge
Qm = volumetric flow rate, liters per minute (L/min) 
corrected to 20 [deg]C and 101.325 kilopascals (kPa) (scf per minute 
(scfm) corrected to 68 [deg]F and 1 atmosphere of pressure (atm))
Tn = time duration of each charge, min
%EOv = volume fraction percent of EtO
n = number of EtO charges
MW = molecular weight of EtO, 44.05 grams per gram-mole (g/g-mole) 
(44.05 pounds per pound-mole (lb/lb-mole))
SV = standard volume, 24.05 liters per gram-mole (L/g-mole) at 20 
[deg]C and 101.325 kPa (385.1 scf per pound-mole (scf/lb-mole) at 68 
[deg]F and 1 atm).

    (B) Determine the adjustment factor (f) using equation 8 to this 
paragraph. Determine the mass of EtO sent to controls from all non-SCV 
affected sources, I, using equation 4 to this paragraph. For facilities 
where EtO use is less than 4 tpy, if not all Group 2 room air emissions 
are routed to a control device, do not include Group 2 room air 
emissions in I, and subtract 0.002 from this factor.

[[Page 24181]]

[GRAPHIC] [TIFF OMITTED] TR05AP24.035


Where:

f = Adjustment factor.
I = Mass of non-SCV EtO routed to control devices over the previous 
30 operating days
MFac = Facility EtO use over the previous 30-operating 
days, in pounds, as determined in accordance with equation 11 of 
Sec.  63.364(i)(2)

[GRAPHIC] [TIFF OMITTED] TR05AP24.036


Where:

I = Mass of non-SCV EtO routed to control devices over the previous 
30 operating days
Mc,i = The 30-operating day total mass sent to controls 
(i.e., monitoring data at the inlet of the control system) for each 
non-SCV emission stream, as calculated using equation A-3 and 
determined in accordance with appendix A to this subpart. The term 
``Mc,i'' as used in this equation is equivalent to the 
term ``E30day'' as designated in equation A-3.
i = Non-SCV emission stream index.
n = Total number of non-SCV emission streams.

    (C)(1) Determine the mass rate of EtO sent to controls during the 
previous 30 days using equation 5 to this paragraph.
[GRAPHIC] [TIFF OMITTED] TR05AP24.037


Where:

MSCV = Total mass of EtO sent to controls over the 
previous 30 operating days, g/hr (lb/hr)
f = Adjustment factor
MSCV,n = Theoretical mass of EtO sent to controls per 
charge per chamber, g (lb)
n = Total number of charges during the previous 30 operating days

    (2) If both this approach is chosen and the SCV is (or SCVs are) 
combined with another emission stream, then the owner or operator 
cannot monitor the point after the combination occurs.
    (ii) Room air emissions. If room air emissions are both subject to 
an emission standard and split between two or more control systems, 
then monitoring must be conducted for room air emissions before they 
are combined with other streams.
    (2) EtO CEMS on exhaust configurations. Exhaust gases from the 
emission sources under this subpart exhaust to the atmosphere through a 
variety of different configurations, including but not limited to 
individual stacks, a common stack configuration, or a main stack plus a 
bypass stack. For the CEMS used to provide data under this subpart, the 
continuous monitoring system installation requirements for these 
exhaust configurations are as follows:
    (i) Single unit-single stack configurations. For an emission source 
that exhausts to the atmosphere through a single, dedicated stack, you 
shall either install the required CEMS in the stack or at a location in 
the ductwork downstream of all emissions control devices, where the 
pollutant and diluents concentrations are representative of the 
emissions that exit to the atmosphere.
    (ii) Unit utilizing common stack with other emission source(s). 
When an emission source utilizes a common stack with one or more other 
emission sources, but no emission sources not subject to this rule, you 
shall either:
    (A) Install the required CEMS in the duct from each emission 
source, leading to the common stack; or
    (B) Install the required CEMS in the common stack.
    (iii) Unit(s) utilizing common stack with non-commercial 
sterilization emission source(s). (A) When one or more emission sources 
shares a common stack with one or more emission sources not subject to 
this rule, you shall either:
    (1) Install the required CEMS in the ducts from each emission 
source that is subject to this rule, leading to the common stack; or
    (2) Install the required CEMS described in this section in the 
common stack and attribute all of the emissions measured at the common 
stack to the emission source(s).
    (B) If you choose the common stack monitoring option:
    (1) For each hour in which valid data are obtained for all 
parameters, you must calculate the pollutant emission rate; and
    (2) You must assign the calculated pollutant emission rate to each 
of the units subject to the rule that share the common stack.
    (iv) Unit with multiple parallel control devices with multiple 
stacks. If the exhaust gases from an emission source, which is 
configured such that emissions are controlled with multiple parallel 
control devices or multiple series of control devices are discharged to 
the atmosphere through more than one stack, you shall install the 
required CEMS described in each of the multiple stacks. You shall 
calculate hourly, flow-weighted, average pollutant emission rates for 
the unit as follows:
    (A) Calculate the pollutant emission rate at each stack or duct for 
each hour in which valid data are obtained for all parameters;
    (B) Multiply each calculated hourly pollutant emission rate at each 
stack or duct by the corresponding hourly gas flow rate at that stack 
or duct;

[[Page 24182]]

    (C) Sum the products determined under paragraph (f)(2)(iv)(B) of 
this section; and
    (D) Divide the result obtained in paragraph (f)(2)(I(C) of this 
section by the total hourly gas flow rate for the unit, summed across 
all of the stacks or ducts.
    (g) PTE monitoring. If you are required to operate all or a portion 
of your sterilization facility under PTE conditions, you must:
    (1) Initial compliance. Demonstrate initial procedures in Sec.  
63.365(g)(1) and continued compliance with the provisions in this 
section. You must follow the requirements of either paragraphs (g)(2) 
and (3) of this section or paragraph (g)(4) of this section.
    (2) Continuous compliance. If you choose to demonstrate continuous 
compliance through volumetric flow rate monitoring, you must monitor 
and record at least every 15 minutes the volumetric flow rate from each 
outlet where air from the PTE is sent using a flow rate monitoring 
system described in paragraph (g)(3) of this section. Monitoring is 
required when the portion of the facility covered by PTE is operated. A 
data acquisition system for the flow rate monitoring system shall 
compute and record each 3-hour average flow rate value, rolled hourly. 
This must be done by first averaging the flow rate readings over a 
clock hour, i.e., beginning and ending on the hour. All data collected 
during the operating hour must be used, even the portion of the 
facility covered by PTE is not operated for a complete hour. Then, the 
average of the previous 3 operating hours must be calculated to 
determine the 3-hour rolling average flow rate. You must maintain the 
3-hour rolling average flow rate above the applicable operating limits 
established during the most recent compliance demonstration.
    (3) Continuous flow rate monitoring system for PTE. You must 
install, operate, calibrate, and maintain instruments, according to the 
requirements in paragraphs (g)(3)(i) through (ix) of this section, for 
continuously measuring and recording the stack gas flow rate to allow 
determination of compliance with the minimum volumetric flow rate 
through the affected stack operating limit(s).
    (i) You must install each sensor of the flow rate monitoring system 
in a location that provides representative measurement of the exhaust 
gas flow rate. The flow rate sensor is that portion of the system that 
senses the volumetric flow rate and generates an output proportional to 
that flow rate.
    (ii) The flow rate monitoring system must be designed to measure 
the exhaust flow rate over a range that extends from a value of at 
least 20 percent less than the lowest expected exhaust flow rate to a 
value of at least 20 percent greater than the highest expected exhaust 
flow rate.
    (iii) The flow rate monitoring system must be equipped with a data 
acquisition and recording system that is capable of recording values 
over the entire range specified in paragraph (g)(3)(ii) of this 
section.
    (iv) The signal conditioner, wiring, power supply, and data 
acquisition and recording system for the flow rate monitoring system 
must be compatible with the output signal of the flow rate sensors used 
in the monitoring system.
    (v) The flow rate monitoring system must be designed to complete a 
minimum of one cycle of operation for each successive 15-minute period.
    (vi) The flow rate sensor must have provisions to determine the 
daily zero and upscale calibration drift (CD) (see sections 3.1 and 8.3 
of Performance Specification 2 in appendix B to Part 60 of this chapter 
for a discussion of CD).
    (A) Conduct the CD tests at two reference signal levels, zero 
(e.g., 0 to 20 percent of span) and upscale (e.g., 50 to 70 percent of 
span).
    (B) The absolute value of the difference between the flow monitor 
response and the reference signal must be equal to or less than 3 
percent of the flow monitor span.
    (vii) You must perform an initial relative accuracy test of the 
flow rate monitoring system according to section 8.2 of Performance 
Specification 6 of appendix B to part 60 of the chapter with the 
exceptions in paragraphs (g)(3)(vii)(A) and (B) of this section.
    (A) The relative accuracy test is to evaluate the flow rate 
monitoring system alone rather than a continuous emission rate 
monitoring system.
    (B) The relative accuracy of the flow rate monitoring system shall 
be no greater than 10 percent of the mean value of the reference method 
data.
    (viii) You must verify the accuracy of the flow rate monitoring 
system at least once per year by repeating the relative accuracy test 
specified in paragraph (g)(3)(vii) of this section.
    (ix) You must operate the flow rate monitoring system and record 
data during all periods of operation of the affected facility including 
periods of startup, shutdown, and malfunction.
    (4) Pressure differential monitor. You must instead install, 
operate, calibrate, and maintain a continuous pressure differential 
monitoring system, as follows, to verify the presence of PTE. You must 
operate this system whenever the facility is in operation. You must 
also maintain the pressure differential at or above 0.007 inches of 
water over a three-hour rolling average.
    (i) This monitoring system must measure the pressure differential 
between the interior and exterior of the PTE, with at least one 
monitoring device located in each room that borders the PTE. These 
monitoring devices shall be designed to provide measurements of 
pressure differential to at least the nearest 0.001 inches of water and 
having a complete cycle time no greater than 5 minutes.
    (ii) A data acquisition system for the monitoring system shall 
compute and record each 3-hour average pressure differential value, 
rolled hourly. This must be done by first averaging the pressure 
differential readings over a clock hour, i.e., beginning and ending on 
the hour. All data collected during the operating hour must be used, 
even in portions of the facility covered by PTE that are not operated 
for a complete hour. Then, the average of the previous 3 operating 
hours must be calculated to determine the 3-hour rolling average 
pressure differential. If data are not recorded from an alternative 
monitoring device, during any malfunction of the principal monitoring 
device(s) or the automatic recorder, you must manually record the 
measured data at least hourly.
    (h) Sterilization chamber end-cycle EtO concentration. As part of 
your monitoring plan, you must document your approach for determining 
the EtO sterilization chamber concentration. If you choose a parametric 
approach you must meet the requirements in paragraph (h)(1) of this 
section and if you choose a direct measurement approach you must meet 
the requirements in paragraph (h)(2) of this section. Alternatively, 
you may petition the administrator for an alternative monitoring 
approach under Sec.  63.8(f).
    (1) If you choose a parametric approach for determining chamber EtO 
concentrations you must document parameter(s) used in the calculation 
to determine of EtO concentrations and the calculation(s) used to 
determine the chamber concentration. Any instrumentation used for 
parametric monitoring must also be identified in the monitoring plan 
and at a minimum this plan should include the following for each 
instrument:
    (i) Parameter measured and measurement principle of the monitor.
    (ii) Instrument name, model number, serial number, and range.
    (iii) Manufacturer recommended operation practices, including daily 
operational check.

[[Page 24183]]

    (iv) Procedures for calibration, the frequency of calibration, and 
accuracy requirements of the calibration.
    (v) Description for how the information from the parameter monitor 
is being collected and stored.
    (2) If you choose a direct measurement approach for determining 
chamber EtO calibrations you must document the procedures used for the 
operation of the instruments. Any instrument used for direct 
measurement of EtO must be identified in the monitoring plan and at a 
minimum this plan must include the following information:
    (i) Instrument name, model number, serial number, and range.
    (ii) Description of the measurement principle and any potential 
interferences.
    (iii) If applicable, the description of the sampling condition 
system.
    (iv) Procedures for calibration, the frequency of calibration, and 
accuracy requirements of the calibration.
    (v) Description for how the information from the parameter monitor 
is being collected and stored.
    (i) EtO usage. If you own or operate a sterilization facility 
subject to the requirements of this subpart you must monitor and record 
on a daily basis the daily and 30-operating day EtO usage according to 
the requirements of this paragraph. Additionally, you must record EtO 
usage for each calendar month.
    (1) Monitor and record on a daily basis, the daily total mass of 
ethylene oxide, in pounds, used at the facility. The daily total mass 
must be determined using the methodology specified in Sec.  
63.365(c)(1)(i) and (ii).
    (2) Determine and record daily the 30-operating day rolling 
ethylene oxide usage rate using equation 6 to this paragraph.
[GRAPHIC] [TIFF OMITTED] TR05AP24.038


Where:

MFac = Facility EtO use over the previous 30 operating 
days, in pounds.
mFac,i = Daily EtO use for operating day i, in pounds, as 
determined in accordance with paragraph (i)(1) of this section
i = Operating day index.

    (3) Determine and record the total mass of EtO used in each 
calendar month.


Sec.  63.365  Test methods and procedures.

    (a) General--(1) Performance testing for facility where EtO use is 
less than 100 pounds per year. If you own or operate an affected source 
at a facility where EtO use is less than 100 lb/yr that is subject to 
an emission standard in Sec.  63.362, you must comply with the 
performance testing requirements in Sec.  63.7, according to the 
applicability in table 6 to this subpart, using the methods in 
paragraph (b) or (c) of this section, following the applicable 
procedures for initial compliance and continuous compliance in 
paragraphs (d), (e), and (f) of this section.
    (2) Facilities subject to capture efficiency. If you are subject to 
capture efficiency requirements in Sec.  63.362, you must follow the 
applicable procedures for initial and continuous compliance in 
paragraph (f) of this section.
    (b) Test methods for facility where EtO use is less than 100 pounds 
per year. You must use the following test methods to determine the 
average mass emissions of EtO in lb/hr at the inlet of a control system 
(MAPCD, i) and/or outlet of a control system or stack 
(EAPCD, o).
    (1) Select the location of the sampling ports and the number of 
traverse points according to Method 1 of appendix A-1 to part 60 of 
this chapter. Alternatively, for ducts less than 0.3 meter (12 in.) in 
diameter, you may choose to locate sample ports according to Method 1A 
of appendix A-1 to part 60 of this chapter.
    (2) Determine the flow rate through the control system exhaust(s) 
continuously during the test period according to either Methods 2, 2A, 
or 2C of appendix A-1 to part 60 of this chapter, as appropriate. If 
using Method 2, 2A, or 2C, you must complete velocity traverses 
immediately before and subsequently after each test run. If your test 
run is greater than 1 hour, you must also complete a velocity traverse 
at least every hour. Average the velocity collected during a test run 
and calculate volumetric flow as outlined in the appropriate method.
    (3) Determine the oxygen and carbon dioxide concentration of the 
effluent according to Method 3A or 3B of appendix A-2 to part 60 of 
this chapter. The manual procedures (but not instrumental procedures) 
of voluntary consensus standard ANSI/ASME PTC 19.10-1981 (incorporated 
by reference, see Sec.  63.14) may be used as an alternative to EPA 
Method 3B.
    (4) Determine the moisture content of the stack gas according to 
Method 4 of appendix A-3 to part 60 of this chapter. Alternatively, you 
may use an on-line technique that has been validated using Method 301 
of appendix A to this part.
    (5) Determine the EtO concentration according to either paragraph 
(b)(5)(i) or (ii) of this section.
    (i) Follow Method 320 of appendix A to this part and the following 
paragraphs (5)(i)(A) through (D).
    (A) The instrumentation used for measurement must have the 
measurement range to properly quantify the EtO in the gas stream. 
Additionally, for outlet emission streams, the instrumentation must 
have a method detection limit an order of magnitude below concentration 
equivalent of the emission limit.
    (B) Instrumentation used must be continuous in nature with an 
averaging time of one minute or less.
    (C) Calibration Spectra and all other analyte spiking required in 
the method must use EtO gaseous cylinder standard(s) which meet the 
criteria found in Performance Specification 19 of appendix B to part 60 
if this chapter.
    (D) Other methods and materials may be used; however, these 
alternative test methods are subject to Administrator approval.
    (ii) Alternatively, ASTM D6348-12 (Reapproved 2020), (incorporated 
by reference, see Sec.  63.14) may be used with the following 
conditions:
    (A) The test plan preparation and implementation in the Annexes to 
ASTM D 6348-12 (R2020), Sections A1 through A8 are mandatory; and
    (B) In ASTM D6348-12 (R2020) Annex A5 (Analyte Spiking Technique), 
the percent (%) R must be determined for each target analyte (equation 
A5.5). In order for the test data to be acceptable

[[Page 24184]]

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 is 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). The %R value for each compound must be 
reported in the test report, and all field measurements must be 
corrected with the calculated %R value for that compound by using 
equation 1 to this paragraph:
[GRAPHIC] [TIFF OMITTED] TR05AP24.039

    (6) Calculate the mass emission of EtO by using equations 2 and 3 
to this paragraph:
[GRAPHIC] [TIFF OMITTED] TR05AP24.040


Where:

MAPCD, i = average inlet mass rate of EtO per hour, lb/hr
CEtO,i = inlet EtO concentration, ppmdv.
Qi = average inlet volumetric flow per hour at standard conditions, 
dscf/hr
44.05 = molecular weight (MW) of EtO, lb/lb-mole
MW/385.1 x 10\6\ = conversion factor, from ppmv at standard 
conditions to lb/cf
EAPCD, o = average outlet mass rate of EtO per hour, lb/
hr
CEtO,o = outlet EtO concentration, ppbdv.
Qo = average outlet volumetric flow per hour at standard 
conditions, dscf/hr
MW/385.1 x 10\9\ = conversion factor, from ppbv at standard 
conditions to lb/cf

    (c) Alternative approach for SCVs for facility where EtO use is 
less than 100 pounds per year. If you do not own or operate a single-
item sterilizer, to demonstrate compliance with the percent emission 
reduction standards for emissions streams that are comprised only of 
SCVs, you may use the following procedures as an alternative to 
paragraph (b) of this section to determine the mass emissions of EtO 
being emitted via sterilization chamber(s) vents prior to the controls.
    (1) Determine the mass (MSCV,n) of EtO used for each 
charge and at each sterilization chamber used during the performance 
tests using the procedures in either paragraph (c)(1)(i) or (ii) of 
this section.
    (i) Weigh the EtO gas cylinder(s) used to charge the sterilizer(s) 
before and after charging. Record these weights to the nearest 45 g 
(0.1 lb) and calculate the theoretical mass (MSCV,n) vented 
to the controls using equation 4 to this paragraph.
[GRAPHIC] [TIFF OMITTED] TR05AP24.041


Where:

     MSCV,n = Theoretical total mass of EtO vented to 
controls per charge, g (lb)
     Mcharge = total mass of sterilizer gas charge, g 
(lb)
     %E.O.w = weight percent of EtO

    (ii) Install a calibrated rate meter at the sterilizer inlet(s) and 
continuously measure the flow rate (Qm) and duration of each 
sterilizer charge. Calculate the theoretical mass (MSCV,n) 
vented to the controls using equation 5 to this paragraph.
[GRAPHIC] [TIFF OMITTED] TR05AP24.042


Where:

     MSCV,n = Total mass of EtO sent to controls per 
charge
     Qm = volumetric flow rate, liters per minute (L/min) 
corrected to 20 [deg]C and

[[Page 24185]]

101.325 kilopascals (kPa) (scf per minute (scfm) corrected to 68 
[deg]F and 1 atmosphere of pressure (atm))
     Tn = time duration of each charge, min
     n = number of EtO charges
     %E.O.v = volume fraction percent of EtO
     MW = molecular weight of EtO, 44.05 grams per gram-mole (g/g-
mole) (44.05 pounds per pound-mole (lb/lb-mole))
     SV = standard volume, 24.05 liters per gram-mole (L/g-mole) at 
20 [deg]C and 101.325 kPa (385.1 scf per pound-mole (scf/lb-mole) at 
68 [deg]F and 1 atm).

    (2) Determine the mass rate of EtO sent to controls during the 
performance test using equation 6 to this paragraph.
[GRAPHIC] [TIFF OMITTED] TR05AP24.043


Where:

     MSCV = Total mass of EtO sent to controls per hour, 
g/hr (lb/hr)
     MSCV,n = Total mass of EtO sent to controls per 
charge per chamber, g (lb)
     Tt = Total time of the performance test, hour
     n = Total number of charges during testing period
     f = Portion of EtO use that is assumed to be routed to the 
control system (0.93 if aeration is conducted in separate vessel; 
0.98 otherwise)

    (d) Compliance determination for facility where EtO use is less 
than 100 pounds per year. Each compliance demonstration shall consist 
of three separate runs using the applicable methods in paragraph (b) or 
(c) of this section. To determine compliance with the relevant 
standard, arithmetic mean of the three runs must be used. These 
procedures may be performed over a run duration of 1-hour (for a total 
of three 1-hour runs), except for the SCV testing from this category, 
where each run shall consist of the entirety of the sterilizer chamber 
evacuation and subsequent washes. The owner or operator may not conduct 
performance tests during periods of malfunction. The owner or operator 
must record the process information that is necessary to document 
operating conditions during the test and include in such record an 
explanation to support that such conditions represent the entire range 
of normal operation, including operational conditions for maximum 
emissions if such emissions are not expected during maximum production. 
The owner or operator must also account for the control system 
residence time when conducting the performance test. Upon request, the 
owner or operator shall make available to the Administrator such 
records as may be necessary to determine the conditions of performance 
tests. The following procedures shall be used to demonstrate compliance 
with a removal efficiency standard. In addition to these procedures, 
the procedures in paragraph (e) of this section must be followed to 
establish the operating parameter limits for each applicable emission 
control(s).
    (1) You may determine the mass rate emissions of the stream prior 
to the control system and at the outlet of the control system using the 
test methods in paragraph (b) of this section. If the vent stream is 
comprised only of one or more SCVs, then you may use the procedures in 
paragraph (c) of this section for the mass rate emissions at the inlet.
    (2) Calculate the total mass of EtO per hour that is routed to the 
control system by summing the mass of EtO per hour from each vent.
    (3) Determine percent emission reduction (%ER) using the equation 7 
to this paragraph:
[GRAPHIC] [TIFF OMITTED] TR05AP24.044


Where:

     % ER = percent emission reduction
     MAPCD,i = total mass of EtO per hour to the control 
device
     EAPCD,o = total mass of EtO per hour from the 
control device

    (4) Repeat these procedures two additional times. The arithmetic 
average percent efficiency of the three runs shall determine the 
overall efficiency of the control system.
    (e) Determination of operating limits for control device(s). If you 
are using performance testing to demonstrate compliance with removal 
efficiency standards, and if you are not demonstrating continual 
compliance with the applicable standard(s) using an EtO CEMS, you must 
also determine the operating limit(s) for each control device and then 
monitor the parameter(s) for each control device. The procedures in the 
following paragraphs shall be used to establish the parameter operating 
limits to be continually monitored in Sec.  63.364.
    (1) Acid-water scrubbers. The procedures in paragraph (e)(1) of 
this section shall be used to determine the operating limits for acid-
water scrubbers.
    (i) Ethylene glycol concentration. For determining the ethylene 
glycol concentration operating limit, you must establish the maximum 
ethylene glycol concentration as the ethylene glycol concentration 
averaged over three test runs; use the sampling and analysis procedures 
in ASTM D3695-88 (incorporated by reference, see Sec.  63.14) to 
determine the ethylene glycol concentration.
    (ii) Scrubber liquor tank level. During the performance test, you 
must monitor and record the scrubber liquor tank level to the nearest 
\1/4\ inch at the end of each of the three test runs. Use the data 
collected during the most recent performance test to calculate the 
average scrubber liquor tank level. This scrubber liquor tank level is 
the maximum operating limit for your scrubber liquor tank. Repeat this 
procedure for every scrubber liquor tank that is included in the 
performance test.
    (iii) Scrubber liquor pH. During the performance test, you must 
monitor and record the scrubber liquor pH at least once every 15 
minutes during each of the three test runs. You must use pH

[[Page 24186]]

monitors as described in Sec.  63.364(b)(3). Use the data collected 
during the most recent performance test to calculate the average 
scrubber pH measured. This scrubber liquor pH is the maximum operating 
limit for your acid-water scrubber. Repeat this procedure for every 
scrubber liquor tank that is included in the performance test.
    (2) Thermal oxidizers. The procedures in this paragraph shall be 
used to determine the operating limits for thermal oxidizers.
    (i) During the performance test, you must monitor and record the 
temperature at least once every 15 minutes during each of the three 
test runs. You must monitor the temperature in the firebox of the 
thermal oxidizer or immediately downstream of the firebox. You must use 
temperature monitors as described in Sec.  63.364(c)(4).
    (ii) Use the data collected during the performance test to 
calculate and record the average temperature for each test run 
maintained during the performance test. The average temperature of the 
test runs is the minimum operating limit for your thermal oxidizer, 
unless it exceeds the recommended maximum oxidation temperature 
provided by the oxidation unit manufacturer. If this occurs, the 
minimum operating limit for your thermal oxidizer consists of the 
recommended maximum oxidation temperature provided by the oxidation 
unit manufacturer.
    (iii) Paragraphs (e)(2)(i) and (ii) of this section must be 
completed for each thermal oxidizer that is involved in the performance 
test.
    (3) Catalytic oxidizers. The procedures in this paragraph shall be 
used to determine the operating limits for catalytic oxidizers.
    (i) Prior to the start of the performance test, you must check the 
catalyst bed for channeling, abrasion, and settling. If problems are 
found during the inspection, you must replace the catalyst bed or take 
other correction action consistent with the manufacturer's 
recommendations.
    (ii) During the performance test, you must monitor and record the 
temperature at the inlet to the catalyst bed and the temperature 
difference across the catalyst bed at least once every 15 minutes 
during each of the three test runs. You must use temperature monitors 
as described in Sec.  63.364(c)(4).
    (iii) Use the data collected during the performance test to 
calculate and record the average temperature at the inlet to the 
catalyst bed and the average temperature difference across the catalyst 
bed maintained for each test run, and then calculate the arithmetic 
averages of the test runs. These arithmetic averages of the test runs 
are the minimum operating limits for your catalytic oxidizer, unless it 
exceeds the recommended maximum oxidation temperature provided by the 
oxidation unit manufacturer. If this occurs, the minimum operating 
limit for your catalytic oxidizer consists of the recommended maximum 
oxidation temperature provided by the oxidation unit manufacturer.
    (iv) Paragraphs (e)(3)(i) through (iii) of this section must be 
completed for each catalytic oxidizer that is involved in the 
performance test.
    (4) Gas/solid reactors. During the performance test, you must 
monitor and record the gas/solid reactor pressure drop at least once 
every 15 minutes during each of the three test runs. Use the data 
collected during the most recent performance test to calculate the gas/
solid reactor pressure measured. This gas/solid reactor pressure is the 
maximum operating limit for your gas/solid. Repeat this procedure for 
every gas/solid reactor that is included in the performance test.
    (5) Other control system for facility where EtO use is less than 
100 pounds per year. If you seek to demonstrate compliance with a 
standard found at Sec.  63.362 with a control device other than an 
acid-water scrubber, catalytic oxidizer, thermal oxidizer, or gas/solid 
reactor, you must provide to the Administrator the information 
requested under Sec.  63.363(e). You must submit a monitoring plan that 
contains the following items: a description of the device; test results 
collected in accordance with Sec.  63.363(e) verifying the performance 
of the device for controlling EtO emissions to the atmosphere to the 
levels required by the applicable standards; the appropriate operating 
parameters that will be monitored, identifying the ongoing QA 
procedures and performance specifications that will be conducted on the 
instruments; the frequency of conducting QA and performance checks; and 
the frequency of measuring and recording to establish continuous 
compliance with the standards. Your monitoring plan is subject to the 
Administrator's approval. Upon approval by the Administrator you must 
install, calibrate, operate, and maintain the monitor(s) approved by 
the Administrator based on the information submitted in your monitoring 
plan. You must include in your monitoring plan proposed performance 
specifications and quality assurance procedures for your monitors. The 
Administrator may request further information and shall approve 
appropriate test methods and procedures.
    (f) Determination of compliance with PTE requirement. If you are 
required to operate any portion of your facility with PTE, you must 
demonstrate initial compliance with the requirements of this subpart by 
following the procedures of paragraphs (f)(1) through (3) of this 
section, as applicable, during the initial compliance demonstration or 
during the initial certification of the CEMS tests.
    (1) Determine the capture efficiency by verifying the capture 
system meets the criteria in section 6 of Method 204 of appendix M to 
part 51 of this chapter and directs all the exhaust gases from the 
enclosure to an add-on control device.
    (2) Ensure that the air passing through all NDOs flows into the 
enclosure continuously. If the facial velocities (FVs) are less than or 
equal to 9,000 meters per hour (492 feet per minute), the continuous 
inward flow of air shall be verified by continuous observation using 
smoke tubes, streamers, tracer gases, or other means approved by the 
Administrator over the period that the volumetric flow rate tests 
required to determine FVs are carried out. If the FVs are greater than 
9,000 meters per hour (492 feet per minute), the direction of airflow 
through the NDOs shall be presumed to be inward at all times without 
verification.
    (3) If you are demonstrating continuous compliance through 
monitoring the volumetric flow rate, you must monitor and record the 
volumetric flow rate (in cubic feet per second) from the PTE through 
the stack(s) at least once every 15 minutes during each of the three 
test runs. Use the data collected during the most recent compliance 
demonstration to calculate the average volumetric flow rate measured 
during the compliance demonstration. This volumetric flow rate is the 
minimum operating limit for the stack. Repeat this procedure for every 
stack that is included in the compliance demonstration.


Sec.  63.366  Reporting requirements.

    (a) General requirements. The owner or operator of an affected 
source subject to the emissions standards in Sec.  63.362 must fulfill 
all reporting requirements in Sec.  63.10(a), (d), (e), and (f), 
according to the applicability in table 6 to this subpart. These 
reports will be made to the Administrator at the appropriate address 
identified in Sec.  63.13 or submitted electronically.
    (b) Initial compliance report submission. You must submit an 
initial compliance report that provides summary, monitoring system

[[Page 24187]]

performance, and deviation information to the Administrator on April 5, 
2027, or once the report template for this subpart has been available 
on the Compliance and Emissions Data Reporting Interface (CEDRI) 
website for one year, whichever date is later, to the EPA via CEDRI, 
which can be accessed through the EPA's Central Data Exchange (CDX) 
(https://cdx.epa.gov/). The EPA will make all the information submitted 
through CEDRI available to the public without further notice to you. Do 
not use CEDRI to submit information you claim as confidential business 
information (CBI). Anything submitted using CEDRI cannot later be 
claimed CBI. You must use the appropriate electronic report template on 
the CEDRI website (https://www.epa.gov/electronic-reporting-air-emissions/cedri) for this subpart. The date report templates become 
available will be listed on the CEDRI website. The report must be 
submitted by the deadline specified in this subpart, regardless of the 
method in which the report is submitted. Although we do not expect 
persons to assert a claim of CBI, if you wish to assert a CBI claim, 
submit a complete report, including information claimed to be CBI, to 
the EPA. The CBI report must be generated using the appropriate form on 
the CEDRI website or an alternate electronic file consistent with the 
extensible markup language (XML) schema listed on the CEDRI website. 
Submit the CBI file on a compact disc, flash drive, or other commonly 
used electronic storage medium and clearly mark the medium as CBI. Mail 
the electronic medium to U.S. EPA/OAQPS/CORE CBI Office, Attention: 
Commercial Sterilization Facilities Sector Lead, MD C404-02, 4930 Old 
Page Rd., Durham, NC 27703. The same file with the CBI omitted must be 
submitted to the EPA via the EPA's CDX as described earlier in this 
paragraph. All CBI claims must be asserted at the time of submission. 
Furthermore, under CAA section 114(c), emissions data is not entitled 
to confidential treatment, and the EPA is required to make emissions 
data available to the public. Thus, emissions data will not be 
protected as CBI and will be made publicly available. Reports of 
deviations from an operating limit shall include all information 
required in Sec.  63.10(c)(5) through (13), as applicable in table 6 to 
this subpart, along with information from any calibration tests in 
which the monitoring equipment is not in compliance with Performance 
Specification 19 in appendix B and Procedure 7 in appendix F to part 60 
of this chapter or the method used for parameter monitoring device 
calibration. Reports shall also include the name, title, and signature 
of the responsible official who is certifying the accuracy of the 
report. If your report is submitted via CEDRI, the certifier's 
electronic signature during the submission process replaces this 
requirement. When no deviations have occurred or monitoring equipment 
has not been inoperative, repaired, or adjusted, such information shall 
be stated in the report. In addition, the summary report shall include:
    (1) The following information:
    (i) Date that facility commenced construction or reconstruction;
    (ii) Hours of commercial sterilization operation over the previous 
12 months; and
    (iii) Monthly EtO use, in tons, over the previous 36 months.
    (iv) If you are electing to determine the mass of EtO sent to the 
control device from the SCV(s) via the procedure in Sec.  
63.364(f)(1)(i), you must report the daily EtO use from each applicable 
chamber for the previous 7 months.
    (v) An indication if you are required to comply with one or more 
combined emission stream limitations. If so, indicate the affected 
sources that are included in each combined emission stream limitation.
    (vi) An indication if you are electing to comply with a site-wide 
emission limit. If you are electing to comply with a site-wide emission 
limit, report the daily EtO use over the previous 7 months.
    (2) If your sterilization facility is demonstrating continuous 
compliance through periodic performance testing, you must report the 
following:
    (i) Control system ID;
    (ii) Control device ID;
    (iii) Control device type; and
    (iv) Recirculation tank ID if an acid-water scrubber is used to 
meet the emission standard and you elect to comply with the maximum 
scrubber liquor height limit;
    (3) You must report the following for each sterilization chamber at 
your facility:
    (i) The sterilization chamber ID;
    (ii) The ID of the control system that the SCV was routed to, if 
applicable;
    (iii) The portion of SCV exhaust that was routed to the control 
system, if applicable;
    (iv) The ID of the EtO CEMS that was used to monitor SCV emissions, 
if applicable;
    (v) The portion of SCV exhaust that was monitored with the EtO 
CEMS, if applicable;
    (vi) The ID of the control system that the CEV was routed to, if 
applicable;
    (vii) The portion of CEV exhaust that was routed to the control 
system, if applicable;
    (viii) The ID of the EtO CEMS that was used to monitor CEV 
emissions, if applicable;
    (ix) The portion of CEV exhaust that was monitored with the EtO 
CEMS, if applicable;
    (4) If emissions from any room in your facility are subject to an 
emission standard, you must report the following for each room where 
there is the potential for EtO emissions:
    (i) Room ID;
    (ii) Documentation of emissions occurring within the room, 
including aeration, EtO storage, EtO dispensing, pre-aeration handling 
of sterilized material, and post-aeration handling of sterilized 
material;
    (iii) The ID of the control system that the room air was routed to, 
if applicable;
    (iv) The portion of room air that was routed to the control system, 
if applicable;
    (v) The ID of the EtO CEMS that was used to monitor room air 
emissions, if applicable;
    (vi) The portion of room air that was monitored with the EtO CEMS, 
if applicable;
    (5) If an EtO CEMS was used to demonstrate continuous compliance 
with an emission standard for more than 30-operating days, you must 
report the following:
    (i) The information specified in section 11 of appendix A to this 
subpart.
    (ii) The affected sources that are included in each inlet that is 
being monitored with EtO CEMS;
    (iii) The IDs of each inlet(s) to and outlet(s) from each control 
system.
    (iv) The daily sum of EtO for each inlet, along with 30-operating 
day rolling sums.
    (v) The daily sum of EtO emissions from each outlet of the control 
system, along with 30-operating day rolling sums.
    (vi) For each day, calculate and report the daily mass emission 
limit that the control system must achieve based on the previous 30 
days of data. For control systems with multiple emission streams, and 
complying with a combined emission stream limitation in Sec.  63.362(i) 
or a SWEL in Sec.  63.362(j), report the daily 30-operating day mass 
emission limit as determined in accordance with CES in Sec.  
63.362(i)(1)(i) and (i)(2)(i) or with Sec.  63.362(j)(1)(i) and 
(j)(2)(i), as applicable.
    (vii) For each day, the mass of EtO emitted from the control system 
over the previous 30 operating days.
    (6) If any portion of your facility is required to be operated with 
PTE, you must report the following:

[[Page 24188]]

    (i) If you are choosing to demonstrate continuous compliance 
through the use of volumetric flow rate monitoring, you must report the 
3-hr rolling average, rolled hourly volumetric flow from each outlet 
where air from the PTE is sent, in cubic feet per second.
    (ii) If you are choosing to demonstrate continuous compliance 
through use of differential pressure monitoring, you must report the 3-
hr rolling average, rolled hourly pressure differential reading, in 
inches water.
    (7) If you are complying with the requirement to follow the best 
management practice to limit sterilization chamber concentration of EtO 
to 1 ppmv prior to opening the sterilization chamber door, you must 
provide a certification from your responsible official that this 
approach is being followed and you are meeting the monitoring 
requirements at Sec.  63.362(h).
    (8) If you own or operate an existing collection of Group 2 room 
air emissions at an area source facility and facility EtO use is less 
than 4 tpy, you must report the following for each room where there are 
Group 2 room air emissions:
    (i) Room ID;
    (ii) Number of room air changes per hour;
    (iii) Room temperature, in degrees Celsius; and
    (iv) EtO concentration, in ppmv dry basis (ppbvd).
    (9) If you own or operate an existing collection of Group 2 room 
air emissions at an area source facility and EtO use is less than 4 
tpy, you are not required to report the information in paragraph (b)(8) 
of this section if you meet the following requirements:
    (i) You are complying with the best management practice to limit 
sterilization chamber concentration of EtO to 1 ppmv prior to opening 
the sterilization chamber door; and
    (ii) The requirements of Sec.  63.363 are met.
    (10) Report the number of deviations to meet an applicable 
standard. For each instance, report the date, time, the cause and 
duration of each deviation. For each deviation the report must include 
a list of the affected sources or equipment, an estimate of the 
quantity of each regulated pollutant emitted over any emission limit, 
and a description of the method used to determine the emissions.
    (c) Quarterly compliance report submission. You must submit 
compliance reports that provide summary, monitoring system performance, 
and deviation information to the Administrator within 30 days following 
the end of each calendar quarter. Beginning on April 5, 2027, or once 
the report template for this subpart has been available on the 
Compliance and Emissions Data Reporting Interface (CEDRI) website for 1 
year, whichever date is later, submit all subsequent reports to the EPA 
via CEDRI, which can be accessed through the EPA's CDX (https://cdx.epa.gov/). The EPA will make all the information submitted through 
CEDRI available to the public without further notice to you. Do not use 
CEDRI to submit information you claim as CBI. Anything submitted using 
CEDRI cannot later be claimed CBI. You must use the appropriate 
electronic report template on the CEDRI website (https://www.epa.gov/electronic-reporting-air-emissions/cedri) for this subpart. The date 
report templates become available will be listed on the CEDRI website. 
The report must be submitted by the deadline specified in this subpart, 
regardless of the method in which the report is submitted. Although we 
do not expect persons to assert a claim of CBI, if you wish to assert a 
CBI claim, submit a complete report, including information claimed to 
be CBI, to the EPA. The CBI report must be generated using the 
appropriate form on the CEDRI website or an alternate electronic file 
consistent with the XML schema listed on the CEDRI website. Submit the 
CBI file on a compact disc, flash drive, or other commonly used 
electronic storage medium and clearly mark the medium as CBI. Mail the 
electronic medium to U.S. EPA/OAQPS/CORE CBI Office, Attention: 
Commercial Sterilization Facilities Sector Lead, MD C404-02, 4930 Old 
Page Rd., Durham, NC 27703. The same file with the CBI omitted must be 
submitted to the EPA via the EPA's CDX as described earlier in this 
paragraph. All CBI claims must be asserted at the time of submission. 
Furthermore, under CAA section 114(c), emissions data is not entitled 
to confidential treatment, and the EPA is required to make emissions 
data available to the public. Reports of deviations from an operating 
limit shall include all information required in Sec.  63.10(c)(5) 
through (13), as applicable in table 6 to this subpart, and information 
from any calibration tests in which the monitoring equipment is not in 
compliance with Performance Specification 19 in appendix B and 
Procedure 7 in appendix F to part 60 of this chapter or the method used 
for parameter monitoring device calibration. Reports shall also include 
the name, title, and signature of the responsible official who is 
certifying the accuracy of the report. If your report is submitted via 
CEDRI, the certifier's electronic signature during the submission 
process replaces this requirement. When no deviations have occurred or 
monitoring equipment has not been inoperative, repaired, or adjusted, 
such information shall be stated in the report. In addition, the 
summary report shall include:
    (1) The information listed in paragraphs (b)(1)(i) through (vi) of 
this section, with the exception that monthly EtO use, in tons, only 
needs reported for the previous 12 months;
    (2) If your sterilization facility is demonstrating continuous 
compliance through periodic performance testing, you must report the ID 
for any control system that has not operated since the end of the 
period covered by the previous compliance report. If a control system 
has commenced operation since end of the period covered by the previous 
compliance report, or if any of the information in paragraphs (b)(2)(i) 
through (iv) of this section has changed for a control system that was 
included in the previous compliance report, you must report the 
information in paragraphs (b)(2)(i) through (iv) of this section for 
those control systems;
    (3) You must report the ID for any sterilization chamber that has 
not operated since then end of the period covered by the previous 
compliance report. If a sterilization chamber has commenced operation 
since the end of the period covered by the previous compliance report, 
or if any of the information in paragraphs (b)(3)(i) through (ix) of 
this section has changed for a sterilization chamber that was included 
in the previous compliance report, you must report the information in 
paragraphs (b)(3)(i) through (ix) of this section for those 
sterilization chambers;
    (4) If emissions from any room in your facility are subject to an 
emission standard, you must report the ID for any room where there has 
not been the potential for EtO emissions since the end of the period 
covered by the previous compliance report. If a room has had the 
potential for EtO emissions since the end of the period covered by the 
previous compliance report, or if any of the information in paragraphs 
(b)(4)(i) through (vi) of this section has changed for a room where 
there is the potential for EtO emissions that was included in the 
previous compliance report, you must report the information in 
paragraphs (b)(4)(i) through (vi) of this section for those rooms;
    (5) If an EtO CEMS was used to demonstrate continuous compliance, 
you must report the information specified in paragraphs (b)(5)(i) 
through (vi) of this section.

[[Page 24189]]

    (6) If any portion of your facility is required to be operated with 
PTE, you must report the information listed in paragraph (b)(6) of this 
section.
    (7) If you are complying with the requirement to follow the best 
management practice to limit sterilization chamber concentration of EtO 
to 1 ppmv prior to opening the sterilization chamber door, you must 
provide a certification from your responsible official that this 
approach is being followed and you are meeting the monitoring 
requirements at Sec.  63.362(h).
    (8) If you own or operate an existing collection of Group 2 room 
air emissions at an area source facility and facility EtO use is less 
than 4 tpy, you must report the ID for any room where Group 2 room air 
emissions have ceased since end of the period covered by the previous 
compliance report. If a room has had Group 2 room air emissions since 
the end of the period covered by the previous compliance report, or if 
any of the information in paragraphs (b)(8)(i) through (iv) of this 
section has changed for a room where there are Group 2 room air 
emissions that were included in the previous compliance report, you 
must report the information in paragraphs (b)(8)(i) through (iv) of 
this section for each room where there are Group 2 room air emissions.
    (9) If you own or operate an existing collection of Group 2 room 
air emissions at an area source facility and facility EtO use is less 
than 4 tpy, you are not required to report the information in paragraph 
(c)(8) of this section if you meet the requirements in paragraph (b)(9) 
of this section.
    (10) Report the number of deviations to meet an applicable 
standard. For each instance, report the date, time, the cause, and 
duration of each deviation. For each deviation, the report must include 
a list of the affected sources or equipment, the quantity of each 
regulated pollutant emitted over any emission limit, and a description 
of the method used to determine the emissions.
    (d) Construction and reconstruction application. You must fulfill 
all requirements for construction or reconstruction of a facility in 
Sec.  63.5, according to the applicability in table 6 to this subpart, 
and in this paragraph.
    (1) Applicability. (i) This paragraph (d) and Sec.  63.5 implement 
the preconstruction review requirements of section 112(i)(1) for 
facilities subject to these emissions standards. In addition, this 
paragraph (d) and Sec.  63.5 include other requirements for constructed 
and reconstructed facilities that are or become subject to these 
emissions standards.
    (ii) After April 5, 2024, the requirements in this section and in 
Sec.  63.5 apply to owners or operators who construct a new facility or 
reconstruct a facility subject to these emissions standards after April 
5, 2024. New or reconstructed facilities subject to these emissions 
standards with an initial startup date before the effective date are 
not subject to the preconstruction review requirements specified in 
paragraphs (b)(2) and (3) of this section and Sec.  63.5(d)(3) and (4) 
and (e).
    (2) Advance approval. After April 5, 2024, whether or not an 
approved permit program is effective in the jurisdictional authority in 
which a facility is (or would be) located, no person may construct a 
new facility or reconstruct a facility subject to these emissions 
standards, or reconstruct a facility such that the facility becomes a 
facility subject to these emissions standards, without obtaining 
advance written approval from the Administrator in accordance with the 
procedures specified in paragraph (b)(3) of this section and Sec.  
63.5(d)(3) and (4) and (e).
    (3) Application for approval of construction or reconstruction. The 
provisions of paragraph (b)(3) of this section and Sec.  63.5(d)(3) and 
(4) implement section 112(i)(1) of the Act.
    (i) General application requirements. (A) An owner or operator who 
is subject to the requirements of paragraph (b)(2) of this section 
shall submit to the Administrator an application for approval of the 
construction of a new facility subject to these emissions standards, 
the reconstruction of a facility subject to these emissions standards, 
or the reconstruction of a facility such that the facility becomes a 
facility subject to these emissions standards. The application shall be 
submitted as soon as practicable before the construction or 
reconstruction is planned to commence (but not sooner than the 
effective date) if the construction or reconstruction commences after 
the effective date. The application shall be submitted as soon as 
practicable before the initial startup date but no later than 60 days 
after the effective date if the construction or reconstruction had 
commenced and the initial startup date had not occurred before the 
effective date. The application for approval of construction or 
reconstruction may be used to fulfill the initial notification 
requirements of paragraph (e)(1)(iii) of this section. The owner or 
operator may submit the application for approval well in advance of the 
date construction or reconstruction is planned to commence in order to 
ensure a timely review by the Administrator and that the planned 
commencement date will not be delayed.
    (B) A separate application shall be submitted for each construction 
or reconstruction. Each application for approval of construction or 
reconstruction shall include at a minimum:
    (1) The applicant's name and address.
    (2) A notification of intention to construct a new facility subject 
to these emissions standards or make any physical or operational change 
to a facility subject to these emissions standards that may meet or has 
been determined to meet the criteria for a reconstruction, as defined 
in Sec.  63.2.
    (3) The address (i.e., physical location) or proposed address of 
the facility.
    (4) An identification of the relevant standard that is the basis of 
the application.
    (5) The expected commencement date of the construction or 
reconstruction.
    (6) The expected completion date of the construction or 
reconstruction.
    (7) The anticipated date of (initial) startup of the facility.
    (8) The type and quantity of hazardous air pollutants emitted by 
the facility, reported in units and averaging times and in accordance 
with the test methods specified in the standard, or if actual emissions 
data are not yet available, an estimate of the type and quantity of 
hazardous air pollutants expected to be emitted by the facility 
reported in units and averaging times specified. The owner or operator 
may submit percent reduction information, if the standard is 
established in terms of percent reduction. However, operating 
parameters, such as flow rate, shall be included in the submission to 
the extent that they demonstrate performance and compliance.
    (9) Other information as specified in paragraph (b)(3)(ii) of this 
section and Sec.  63.5(d)(3).
    (C) An owner or operator who submits estimates or preliminary 
information in place of the actual emissions data and analysis required 
in paragraphs (b)(3)(i)(B)(8) and (b)(3)(ii) of this section shall 
submit the actual, measured emissions data and other correct 
information as soon as available but no later than with the 
notification of compliance status required in paragraph (c)(2) of this 
section.
    (ii) Application for approval of construction. Each application for 
approval of construction shall include, in addition to the information 
required in paragraph (b)(3)(i)(B) of this section, technical 
information describing the proposed nature, size, design, operating 
design capacity, and method of

[[Page 24190]]

operation of the facility subject to these emissions standards, 
including an identification of each point of emission for each 
hazardous air pollutant that is emitted (or could be emitted) and a 
description of the planned air pollution control system (equipment or 
method) for each emission point. The description of the equipment to be 
used for the control of emissions shall include each control device for 
each hazardous air pollutant and the estimated control efficiency 
(percent) for each control device. The description of the method to be 
used for the control of emissions shall include an estimated control 
efficiency (percent) for that method. Such technical information shall 
include calculations of emission estimates in sufficient detail to 
permit assessment of the validity of the calculations. An owner or 
operator who submits approximations of control efficiencies under 
paragraph (b)(3) of this section shall submit the actual control 
efficiencies as specified in paragraph (b)(3)(i)(C) of this section.
    (4) Approval of construction or reconstruction based on prior 
jurisdictional authority preconstruction review. (i) The Administrator 
may approve an application for construction or reconstruction specified 
in paragraphs (b)(2) and (3) of this section and Sec.  63.5(d)(3) and 
(4) if the owner or operator of a new or reconstructed facility who is 
subject to such requirement demonstrates to the Administrator's 
satisfaction that the following conditions have been (or will be) met:
    (A) The owner or operator of the new or reconstructed facility 
subject to these emissions standards has undergone a preconstruction 
review and approval process in the jurisdictional authority in which 
the facility is (or would be) located before the effective date and has 
received a federally enforceable construction permit that contains a 
finding that the facility will meet these emissions standards as 
proposed, if the facility is properly built and operated;
    (B) In making its finding, the jurisdictional authority has 
considered factors substantially equivalent to those specified in Sec.  
63.5(e)(1).
    (ii) The owner or operator shall submit to the Administrator the 
request for approval of construction or reconstruction no later than 
the application deadline specified in paragraph (b)(3)(i) of this 
section. The owner or operator shall include in the request information 
sufficient for the Administrator's determination. The Administrator 
will evaluate the owner or operator's request in accordance with the 
procedures specified in Sec.  63.5. The Administrator may request 
additional relevant information after the submittal of a request for 
approval of construction or reconstruction.
    (e) Notification requirements. The owner or operator of an affected 
source subject to an emissions standard in Sec.  63.362 shall fulfill 
all notification requirements in Sec.  63.9, according to the 
applicability in table 6 to this subpart, and in this paragraph (e).
    (1) Initial notifications. (i) If you own or operate an affected 
source subject to an emissions standard in Sec.  63.362, you may use 
the application for approval of construction or reconstruction under 
paragraph (d)(3)(ii) of this section and Sec.  63.5(d)(3), 
respectively, if relevant to fulfill the initial notification 
requirements.
    (ii) The owner or operator of a new or reconstructed facility 
subject to these emissions standards that has an initial startup date 
after the effective date and for which an application for approval of 
construction or reconstruction is required under paragraph (d)(3) of 
this section and Sec.  63.5(d)(3) and (4) shall provide the following 
information in writing to the Administrator:
    (A) A notification of intention to construct a new facility subject 
to these emissions standards, reconstruct a facility subject to these 
emissions standards, or reconstruct a facility such that the facility 
becomes a facility subject to these emissions standards with the 
application for approval of construction or reconstruction as specified 
in paragraph (d)(3)(i)(A) of this section;
    (B) A notification of the date when construction or reconstruction 
was commenced, submitted simultaneously with the application for 
approval of construction or reconstruction, if construction or 
reconstruction was commenced before the effective date of these 
standards;
    (C) A notification of the date when construction or reconstruction 
was commenced, delivered or postmarked no later than 30 days after such 
date, if construction or reconstruction was commenced after the 
effective date of these standards;
    (D) A notification of the anticipated date of startup of the 
facility, delivered or postmarked not more than 60 days nor less than 
30 days before such date; and
    (E) A notification of the actual date of initial startup of the 
facility, delivered or postmarked within 15 calendar days after that 
date.
    (iii) After the effective date, whether or not an approved permit 
program is effective in the jurisdictional authority in which a 
facility subject to these emissions standards is (or would be) located, 
an owner or operator who intends to construct a new facility subject to 
these emissions standards or reconstruct a facility subject to these 
emissions standards, or reconstruct a facility such that it becomes a 
facility subject to these emissions standards, shall notify the 
Administrator in writing of the intended construction or 
reconstruction. The notification shall be submitted as soon as 
practicable before the construction or reconstruction is planned to 
commence (but no sooner than the effective date of these standards) if 
the construction or reconstruction commences after the effective date 
of the standard. The notification shall be submitted as soon as 
practicable before the initial startup date but no later than 60 days 
after the effective date of this standard if the construction or 
reconstruction had commenced and the initial startup date has not 
occurred before the standard's effective date. The notification shall 
include all the information required for an application for approval of 
construction or reconstruction as specified in paragraph (d)(3) of this 
section and Sec.  63.5(d)(3) and (4). For facilities subject to these 
emissions standards, the application for approval of construction or 
reconstruction may be used to fulfill the initial notification 
requirements of Sec.  63.9.
    (2) If an owner or operator of a facility subject to these 
emissions standards submits estimates or preliminary information in the 
application for approval of construction or reconstruction required in 
paragraph (d)(3)(ii) of this section and Sec.  63.5(d)(3), 
respectively, in place of the actual emissions data or control 
efficiencies required in paragraphs (d)(3)(i)(B)(8) and (b)(3)(ii) of 
this section, the owner or operator shall submit the actual emissions 
data and other correct information as soon as available but no later 
than with the initial notification of compliance status.
    (3) If you own or operate an affected source subject to an 
emissions standard in Sec.  63.362, you must also include the amount of 
EtO used at the facility during the previous consecutive 12-month 
period in the initial notification report required by Sec.  63.9(b)(2) 
and (3). For new sterilization facilities subject to this subpart, the 
amount of EtO used at the facility shall be an estimate of expected use 
during the first consecutive 12-month period of operation.
    (4) Beginning October 7, 2024, you must submit all subsequent 
Notification of Compliance Status reports in PDF formatto the EPA 
following the

[[Page 24191]]

procedure specified in Sec.  63.9(k), except any medium submitted 
through mail must be sent to the attention of the Commercial 
Sterilization Sector Lead.
    (f) Performance test submission. Beginning on June 4, 2024, within 
60 days after the date of completing each performance test required by 
this subpart, you must submit the results of the performance test 
following the procedures specified in paragraphs (f)(1) through (3) of 
this section.
    (1) Data collected using test methods supported by the EPA's 
Electronic Reporting Tool (ERT) as listed on the EPA's ERT website 
(https://www.epa.gov/electronic-reporting-air-emissions/electronic-reporting-tool-ert) at the time of the test. Submit the results of the 
performance test to the EPA via the CEDRI, which can be accessed 
through the EPA's CDX (https://cdx.epa.gov/). The data must be 
submitted in a file format generated using the EPA's ERT. 
Alternatively, you may submit an electronic file consistent with the 
XML schema listed on the EPA's ERT website.
    (2) Data collected using test methods that are not supported by the 
EPA's ERT as listed on the EPA's ERT website at the time of the test. 
The results of the performance test must be included as an attachment 
in the ERT or an alternate electronic file consistent with the XML 
schema listed on the EPA's ERT website. Submit the ERT generated 
package or alternative file to the EPA via CEDRI.
    (3) CBI. Do not use CEDRI to submit information you claim as CBI. 
Anything submitted using CEDRI cannot later be claimed CBI. Although we 
do not expect persons to assert a claim of CBI, if you wish to assert a 
CBI claim for some of the information submitted under paragraph 
(f)(1)(i) or (ii) of this section, you must submit a complete file, 
including information claimed to be CBI, to the EPA. The file must be 
generated using the EPA's ERT or an alternate electronic file 
consistent with the XML schema listed on the EPA's ERT website. Submit 
the file on a compact disc, flash drive, or other commonly used 
electronic storage medium and clearly mark the medium as CBI. Mail the 
electronic medium to U.S. EPA/OAQPS/CORE CBI Office, Attention: Group 
Leader, Measurement Policy Group, MD C404-02, 4930 Old Page Rd., 
Durham, NC 27703. The same file with the CBI omitted must be submitted 
to the EPA via the EPA's CDX as described in paragraphs (f)(1)(i) and 
(ii) of this section. All CBI claims must be asserted at the time of 
submission. Furthermore, under CAA section 114(c), emissions data is 
not entitled to confidential treatment, and the EPA is required to make 
emissions data available to the public. Thus, emissions data will not 
be protected as CBI and will be made publicly available.
    (g) Performance evaluation submission. Beginning on June 4, 2024, 
within 60 days after the date of completing each CEMS performance 
evaluation (as defined in Sec.  63.2), you must submit the results of 
the performance evaluation following the procedures specified in 
paragraphs (g)(1) through (3) of this section.
    (1) Performance evaluations of CEMS measuring relative accuracy 
test audit (RATA) pollutants that are supported by the EPA's ERT as 
listed on the EPA's ERT website at the time of the evaluation. Submit 
the results of the performance evaluation to the EPA via CEDRI, which 
can be accessed through the EPA's CDX. The data must be submitted in a 
file format generated using the EPA's ERT. Alternatively, you may 
submit an electronic file consistent with the XML schema listed on the 
EPA's ERT website.
    (2) Performance evaluations of CEMS measuring RATA pollutants that 
are not supported by the EPA's ERT as listed on the EPA's ERT website 
at the time of the evaluation. The results of the performance 
evaluation must be included as an attachment in the ERT or an alternate 
electronic file consistent with the XML schema listed on the EPA's ERT 
website. Submit the ERT generated package or alternative file to the 
EPA via CEDRI.
    (3) CBI. Do not use CEDRI to submit information you claim as CBI. 
Anything submitted using CEDRI cannot later be claimed CBI. Although we 
do not expect persons to assert a claim of CBI, if you wish to assert a 
CBI claim for some of the information submitted under paragraph 
(g)(1)(i) or (ii) of this section, you must submit a complete file, 
including information claimed to be CBI, to the EPA. The CBI file must 
be generated using the EPA's ERT or an alternate electronic file 
consistent with the XML schema listed on the EPA's ERT website. Submit 
the CBI file on a compact disc, flash drive, or other commonly used 
electronic storage medium and clearly mark the medium as CBI. Mail the 
electronic medium to U.S. EPA/OAQPS/CORE CBI Office, Attention: Group 
Leader, Measurement Policy Group, MD C404-02, 4930 Old Page Rd., 
Durham, NC 27703. The same file with the CBI omitted must be submitted 
to the EPA via the EPA's CDX as described in paragraphs (g)(1)(i) and 
(ii) of this section. All CBI claims must be asserted at the time of 
submission. Furthermore, under CAA section 114(c), emissions data is 
not entitled to confidential treatment, and the EPA is required to make 
emissions data available to the public. Thus, emissions data will not 
be protected as CBI and will be made publicly available.
    (h) Extensions for CDX/CEDRI outages. If you are required to 
electronically submit a report through CEDRI in the EPA's CDX, you may 
assert a claim of EPA system outage for failure to timely comply with 
that reporting requirement. To assert a claim of EPA system outage, you 
must meet the requirements outlined in paragraphs (h)(1) through (7) of 
this section.
    (1) You must have been or will be precluded from accessing CEDRI 
and submitting a required report within the time prescribed due to an 
outage of either the EPA's CEDRI or CDX systems.
    (2) The outage must have occurred within the period of time 
beginning five business days prior to the date that the submission is 
due.
    (3) The outage may be planned or unplanned.
    (4) You must submit notification to the Administrator in writing as 
soon as possible following the date you first knew, or through due 
diligence should have known, that the event may cause or has caused a 
delay in reporting.
    (5) You must provide to the Administrator a written description 
identifying:
    (i) The date(s) and time(s) when CDX or CEDRI was accessed and the 
system was unavailable;
    (ii) A rationale for attributing the delay in reporting beyond the 
regulatory deadline to EPA system outage;
    (iii) A description of measures taken or to be taken to minimize 
the delay in reporting; and
    (iv) The date by which you propose to report, or if you have 
already met the reporting requirement at the time of the notification, 
the date you reported.
    (6) The decision to accept the claim of EPA system outage and allow 
an extension to the reporting deadline is solely within the discretion 
of the Administrator.
    (7) In any circumstance, the report must be submitted 
electronically as soon as possible after the outage is resolved.
    (i) Extensions for force majeure events. If you are required to 
electronically submit a report through CEDRI in the EPA's CDX, you may 
assert a claim of force majeure for failure to timely comply with that 
reporting requirement. To assert a claim of force majeure, you must 
meet the requirements outlined in paragraphs (i)(1) through (5) of this 
section.

[[Page 24192]]

    (1) You may submit a claim if a force majeure event is about to 
occur, occurs, or has occurred or there are lingering effects from such 
an event within the period of time beginning five business days prior 
to the date the submission is due. For the purposes of this section, a 
force majeure event is defined as an event that will be or has been 
caused by circumstances beyond the control of the affected facility, 
its contractors, or any entity controlled by the affected facility that 
prevents you from complying with the requirement to submit a report 
electronically within the time period prescribed. Examples of such 
events are acts of nature (e.g., hurricanes, earthquakes, or floods), 
acts of war or terrorism, or equipment failure or safety hazard beyond 
the control of the affected facility (e.g., large scale power outage).
    (2) You must submit notification to the Administrator in writing as 
soon as possible following the date you first knew, or through due 
diligence should have known, that the event may cause or has caused a 
delay in reporting.
    (3) You must provide to the Administrator:
    (i) A written description of the force majeure event;
    (ii) A rationale for attributing the delay in reporting beyond the 
regulatory deadline to the force majeure event;
    (iii) A description of measures taken or to be taken to minimize 
the delay in reporting; and
    (iv) The date by which you propose to report, or if you have 
already met the reporting requirement at the time of the notification, 
the date you reported.
    (4) The decision to accept the claim of force majeure and allow an 
extension to the reporting deadline is solely within the discretion of 
the Administrator.
    (5) In any circumstance, the reporting must occur as soon as 
possible after the force majeure event occurs.


Sec.  63.367  Recordkeeping requirements.

    (a) If you own or operate an affected source subject to Sec.  
63.362, you must comply with the recordkeeping requirements in Sec.  
63.10(a) through (c), according to the applicability in table 6 to this 
subpart, and in this section. All records required to be maintained by 
this subpart or a subpart referenced by this subpart shall be 
maintained in such a manner that they can be readily accessed and are 
suitable for inspection.
    (b) You must maintain the previous five years of records specified 
in Sec.  63.366(b) and (c), as applicable.
    (c) You must maintain the previous five years of records for 
compliance tests and associated data analysis, as applicable.
    (d) Any records required to be maintained by this subpart that are 
submitted electronically via the EPA's CEDRI may be maintained in 
electronic format. This ability to maintain electronic copies does not 
affect the requirement for facilities to make records, data, and 
reports available upon request to a delegated air agency or the EPA as 
part of an on-site compliance evaluation.
    (e) If you are using an EtO CEMS to demonstrate continuous 
compliance, you must maintain the previous five years of records for 
all required certification and QA tests.
    (f) For each deviation from an emission limit, operating limit, or 
best management practice, you must keep a record of the information 
specified in paragraph (g)(1) through (4) of this section. The records 
shall be maintained as specified in Sec.  63.10(b)(1).
    (1) The occurrence and duration of each startup, shutdown, or 
malfunction of process, air pollution control, and monitoring 
equipment.
    (2) In the event that an affected unit does not meet an applicable 
standard, record the number of deviations. For each deviation, record 
the date, time, cause, and duration of each deviation.
    (3) For each failure to meet an applicable standard, record and 
retain a list of the affected sources or equipment, an estimate of the 
quantity of each regulated pollutant emitted over any emission limit 
and a description of the method used to estimate the emissions.
    (4) Record actions taken to minimize emissions in accordance with 
Sec.  63.362(k) and any corrective actions taken to return the affected 
unit to its normal or usual manner of operation.


Sec.  63.368  Implementation and enforcement.

    (a) This subpart can be implemented and enforced by the U.S. EPA or 
a delegated authority such as the applicable State, local, or Tribal 
agency. If the U.S. EPA Administrator has delegated authority to a 
State, local, or Tribal agency, then that agency, in addition to the 
U.S. EPA, has the authority to implement and enforce this subpart. 
Contact the applicable U.S. EPA Regional Office to find out whether 
implementation and enforcement of this subpart are delegated to a 
State, local, or Tribal agency.
    (b) In delegating implementation and enforcement authority of this 
subpart to a State, local, or Tribal agency under subpart E of this 
part, the authorities contained in paragraph (c) of this section are 
retained by the Administrator of U.S. EPA and cannot be transferred to 
the State, local, or Tribal agency.
    (c) The authorities that cannot be delegated to State, local, or 
Tribal agencies are as specified in paragraphs (c)(1) through (5) of 
this section.
    (1) Approval of alternatives to the requirements in Sec. Sec.  
63.360 and 63.362.
    (2) Approval of major alternatives to test methods under Sec.  
63.7(e)(2)(ii) and (f), as defined in Sec.  63.90, and as required in 
this subpart.
    (3) Approval of major alternatives to monitoring under Sec.  
63.8(f), as defined in Sec.  63.90, and as required in this subpart.
    (4) Approval of major alternatives to recordkeeping and reporting 
under Sec.  63.10(f), as defined in Sec.  63.90, and as required in 
this subpart.
    (5) Approval of an alternative to any electronic reporting to the 
EPA required by this subpart.

Table 1 to Subpart O of Part 63--Standards for SCVs

    As required in Sec.  63.362(c), for each SCV, you must meet the 
applicable standard in the following table:

----------------------------------------------------------------------------------------------------------------
                                                                                           You must comply with
            For each . . .                 For which . . .           You must . . .         the standard . . .
----------------------------------------------------------------------------------------------------------------
1. Existing SCV......................  a. Facility EtO use is   i. Continuously reduce   Until April 6, 2026.
                                        at least 10 tpy.         EtO emissions by 99
                                                                 percent \1\.
                                       b. Facility EtO use is   i. Continuously reduce   Until April 6, 2026.
                                        at least 1 tpy but       EtO emissions by 99
                                        less than 10 tpy.        percent \1\.
                                                                ii. Continuously reduce  No later than April 6,
                                                                 EtO emissions by 99.8    2026.
                                                                 percent 2 3.
                                       c. Facility EtO use is   i. Continuously reduce   No later than April 6,
                                        at least 30 tpy.         EtO emissions by 99.99   2026.
                                                                 percent 2 3.
                                       d. Facility EtO use is   i. Continuously reduce   No later than April 6,
                                        at least 10 tpy but      EtO emissions by 99.9    2026.
                                        less than 30 tpy.        percent 2 3.
                                       e. Facility EtO use is   i. Continuously reduce   No later than April 5,
                                        less than 1 tpy.         EtO emissions by 99      2027.
                                                                 percent 2 4.

[[Page 24193]]

 
2. New SCV...........................  a. Initial startup is    i. Continuously reduce   No later than April 5,
                                        on or before April 5,    EtO emissions by 99.99   2024.
                                        2024, and facility EtO   percent 2 5.
                                        use is at least 30 tpy.
                                       b. Initial startup is    i. Continuously reduce   No later than April 5,
                                        on or before April 5,    EtO emissions by 99.9    2024.
                                        2024, and facility EtO   percent 2 5.
                                        use is at least 10 tpy
                                        but less than 30 tpy.
                                       c. Initial startup is    i. Continuously reduce   No later than April 5,
                                        on or before April 5,    EtO emissions by 99.8    2024.
                                        2024, and facility EtO   percent 2 5.
                                        use is at least 1 tpy
                                        but less than 10 tpy.
                                       d. Initial startup is    i. Continuously reduce   No later than April 5,
                                        on or before April 5,    EtO emissions by 99      2024.
                                        2024, and facility EtO   percent 2 6.
                                        use is less than 1 tpy.
                                       e. Initial startup is    i. Continuously reduce   Upon startup of the
                                        after April 5, 2024,     EtO emissions by 99.99   source.
                                        and facility EtO use     percent 2 5.
                                        is at least 30 tpy.
                                       f. Initial startup is    i. Continuously reduce   Upon startup of the
                                        after April 5, 2024,     EtO emissions by 99.9    source.
                                        and facility EtO use     percent 2 5.
                                        is at least 10 tpy but
                                        less than 30 tpy.
                                       g. Initial startup is    i. Continuously reduce   Upon startup of the
                                        after April 5, 2024,     EtO emissions by 99.8    source.
                                        and facility EtO use     percent 2 5.
                                        is at least 1 tpy but
                                        less than 10 tpy.
                                       h. Initial startup is    i. Continuously reduce   Upon startup of the
                                        after April 5, 2024,     EtO emissions by 99      source.
                                        and facility EtO use     percent 2 6.
                                        is less than 1 tpy.
----------------------------------------------------------------------------------------------------------------
\1\ The standard applies if the facility has met or exceeded the specified EtO use within any consecutive 12-
  month period after December 6, 1996.
\2\ If using EtO CEMS to determine compliance, this standard is based on the previous 30 operating days of data.
\3\ The standard applies if the facility has met or exceeded the specified EtO use within any consecutive 12-
  month period after April 7, 2025.
\4\ The standard applies if the facility has used less than 1 tpy of EtO within all consecutive 12-month periods
  after April 6, 2026.
\5\ The standard applies if the facility is expected to meet or exceed the specified EtO use within one year
  after startup. Afterwards, the standard applies if the facility has met or exceeded the specified EtO use
  within any consecutive 12-month period after startup.
\6\ The standard applies if the facility is not expected to meet or exceed 1 tpy of EtO use within one year
  after startup. Afterwards, the standard applies if the facility has used less than 1 tpy of EtO within all
  consecutive 12-month periods after startup.

Table 2 to Subpart O of Part 63--Standards for ARVs

    As required in Sec.  63.362(d), for each ARV, you must meet the 
applicable standard in the following table:

----------------------------------------------------------------------------------------------------------------
                                                                                           You must comply with
            For each . . .                 For which . . .           You must . . .         the standard . . .
----------------------------------------------------------------------------------------------------------------
1. Existing ARV......................  a. Facility EtO use is   i. Continuously reduce   Until April 6, 2026.
                                        at least 10 tpy.         EtO emissions by 99
                                                                 percent \1\.
                                       b. Facility EtO use is   i. Continuously reduce   No later than April 6,
                                        at least 30 tpy.         EtO emissions by 99.9    2026.
                                                                 percent 2 3.
                                       c. Facility EtO use is   i. Continuously reduce   No later than April 6,
                                        at least 10 tpy but      EtO emissions by 99.6    2026.
                                        less than 30 tpy.        percent 2 3.
                                       d. Facility EtO use is   i. Continuously reduce   No later than April 5,
                                        less than 10 tpy.        EtO emissions by 99      2027.
                                                                 percent 2 4.
2. New ARV...........................  a. Initial startup is    i. Continuously reduce   No later than April 5,
                                        on or before April 5,    EtO emissions by 99.9    2024.
                                        2024, and facility EtO   percent 2 5.
                                        use is at least 10 tpy.
                                       b. Initial startup is    i. Continuously reduce   No later than April 5,
                                        on or before April 5,    EtO emissions by 99      2024.
                                        2024, and facility EtO   percent 2 6.
                                        use is less than 10
                                        tpy.
                                       c. Initial startup is    i. Continuously reduce   Upon startup of the
                                        after April 5, 2024,     EtO emissions by 99.9    source.
                                        and facility EtO use     percent 2 5.
                                        is at least 10 tpy.
                                       d. Initial startup is    i. Continuously reduce   Upon startup of the
                                        after April 5, 2024,     EtO emissions by 99      source.
                                        and facility EtO use     percent 2 6.
                                        is less than 10 tpy.
----------------------------------------------------------------------------------------------------------------
\1\ The standard applies if the facility has met or exceeded the specified EtO use within any consecutive 12-
  month period after December 6, 1996.
\2\ If using CEMS to determine compliance, this standard is based on a rolling 30-operating day average.
\3\ The standard applies if the facility has met or exceeded the specified EtO use within any consecutive 12-
  month period after April 7, 2025.
\4\ The standard applies if the facility has used less than 10 tpy of EtO within all consecutive 12-month
  periods after April 6, 2026.
\5\ The standard applies if the facility is expected to meet or exceed the specified EtO use within one year
  after startup. Afterwards, the standard applies if the facility has met or exceeded the specified EtO use
  within any consecutive 12-month period after startup.
\6\ The standard applies if the facility is not expected to meet or exceed 10 tpy of EtO use within one year
  after startup. Afterwards, the standard applies if the facility has used less than 10 tpy of EtO within all
  consecutive 12-month periods after startup.

Table 3 to Subpart O of Part 63--Standards for CEVs

    As required in Sec.  63.362(e), for each CEV, you must meet the 
applicable standard in the following table:

----------------------------------------------------------------------------------------------------------------
                                                                                           You must comply with
            For each . . .                 For which . . .           You must . . .         the standard . . .
----------------------------------------------------------------------------------------------------------------
1. Existing CEV at a major source      a. Not applicable......  i. Continuously reduce   No later than April 5,
 facility.                                                       EtO emissions by 99.94   2027.
                                                                 percent \1\.
2. Existing CEV at an area source      a. Facility EtO use is   i. Continuously reduce   No later than April 6,
 facility.                              at least 60 tpy.         EtO emissions by 99.9    2026.
                                                                 percent 1 2.
                                       b. Facility EtO use is   i. Continuously reduce   No later than April 5,
                                        less than 60 tpy.        EtO emissions by 99      2027.
                                                                 percent 1 3.
3. New CEV at a major source facility  a. Initial startup is    i. Continuously reduce   No later than April 5,
                                        on or before April 5,    EtO emissions by 99.94   2024.
                                        2024.                    percent \1\.

[[Page 24194]]

 
                                       b. Initial startup is    i. Continuously reduce   Upon startup of the
                                        after April 5, 2024.     EtO emissions by 99.94   source.
                                                                 percent \1\.
4. New CEV at an area source facility  a. Initial startup is    i. Continuously reduce   No later than April 5,
                                        on or before April 5,    EtO emissions by 99.9    2024.
                                        2024, and facility EtO   percent 1 4.
                                        use is at least 60 tpy.
                                       b. Initial startup is    i. Continuously reduce   No later than April 5,
                                        on or before April 5,    EtO emissions by 99      2024.
                                        2024, facility EtO use   percent 1 5.
                                        is less than 60 tpy.
                                       c. Initial startup is    i. Continuously reduce   Upon startup of the
                                        after April 5, 2024,     EtO emissions by 99.9    source.
                                        and facility EtO use     percent 1 4.
                                        is at least 60 tpy.
                                       d. Initial startup is    i. Continuously reduce   Upon startup of the
                                        after April 5, 2024,     EtO emissions by 99      source.
                                        facility EtO use is      percent 1 5.
                                        less than 60 tpy.
----------------------------------------------------------------------------------------------------------------
\1\ If using CEMS to determine compliance, this standard is based on a rolling 30-operating day average.
\2\ The standard applies if the facility has met or exceeded the specified EtO use within any consecutive 12-
  month period after April 7, 2025.
\3\ The standard applies if the facility has used less than 60 tpy of EtO within all consecutive 12-month
  periods after April 6, 2026.
\4\ The standard applies if the facility is expected to meet or exceed the specified EtO use within one year
  after startup. Afterwards, the standard applies if the facility has met or exceeded the specified EtO use
  within any consecutive 12-month period after startup.
\5\ The standard applies if the facility is not expected to meet or exceed 60 tpy of EtO use within one year
  after startup. Afterwards, the standard applies if the facility has used less than 60 tpy of EtO within all
  consecutive 12-month periods after startup.

Table 4 to Subpart O of Part 63--Standards for Group 1 Room Air 
Emissions

    As required in Sec.  63.362(f), for your collection of Group 1 room 
air emissions at each facility, you must meet the applicable standard 
in the following table:

----------------------------------------------------------------------------------------------------------------
                                                                                           You must comply with
            For each . . .                 For which . . .           You must . . .       the requirement(s) . .
                                                                                                    .
----------------------------------------------------------------------------------------------------------------
1. Existing collection of Group 1      a. Not applicable......  i. Operate all areas of  No later than April 5,
 room air emissions at a major source                            the facility that        2027.
 facility.                                                       contain Group 1 room
                                                                 air emissions with
                                                                 PTE, with all exhaust
                                                                 gas streams being
                                                                 captured and routed to
                                                                 a control system.
                                                                 Also,
                                                                ii. Continuously reduce
                                                                 EtO emissions by 97
                                                                 percent \1\.
2. Existing collection of Group 1      a. Facility EtO use is   i. Operate all areas of  No later than April 6,
 room air emissions at an area source   at least 40 tpy.         the facility that        2026.
 facility.                                                       contain Group 1 room
                                                                 air emissions with
                                                                 PTE, with all exhaust
                                                                 gas streams being
                                                                 captured and routed to
                                                                 a control system.\2\
                                                                 Also,
                                                                ii. Continuously reduce
                                                                 EtO emissions by 98
                                                                 percent \1\ \2\.
                                       b. Facility EtO use is   i. Operate all areas of  No later than April 5,
                                        less than 40 tpy.        the facility that        2027.
                                                                 contain Group 1 room
                                                                 air emissions with
                                                                 PTE, with all exhaust
                                                                 gas streams being
                                                                 captured and routed to
                                                                 a control system.
                                                                 Also,
                                                                ii. Continuously reduce
                                                                 EtO emissions by 80
                                                                 percent \1\ \3\.
3. New collection of Group 1 room air  a. Initial startup is    i. Operate all areas of  No later than April 5,
 emissions at a major source facility.  on or before April 5,    the facility that        2024.
                                        2024.                    contain Group 1 room
                                                                 air emissions with
                                                                 PTE, with all exhaust
                                                                 gas streams being
                                                                 captured and routed to
                                                                 a control system.
                                                                 Also,
                                                                ii. Continuously reduce
                                                                 EtO emissions by 97
                                                                 percent \1\.
                                       b. Initial startup is    i. Operate all areas of  Upon startup of the
                                        after April 5, 2024.     the facility that        source.
                                                                 contain Group 1 room
                                                                 air emissions with
                                                                 PTE, with all exhaust
                                                                 gas streams being
                                                                 captured and routed to
                                                                 a control system.
                                                                 Also,
                                                                ii. Continuously reduce
                                                                 EtO emissions by 97
                                                                 percent \1\.
4. New collection of Group 1 room air  a. Initial startup is    i. Operate all areas of  No later than April 5,
 emissions at an area source facility.  on or before April 5,    the facility that        2024.
                                        2024, and facility EtO   contain Group 1 room
                                        use is at least 40 tpy.  air emissions with
                                                                 PTE, with all exhaust
                                                                 gas streams being
                                                                 captured and routed to
                                                                 a control system.\4\
                                                                 Also,
                                                                ii. Continuously reduce
                                                                 EtO emissions by 98
                                                                 percent \1\ \4\.
                                       b. Initial startup is    i. Operate all areas of  No later than April 5,
                                        on or before April 5,    the facility that        2024.
                                        2024, and facility EtO   contain Group 1 room
                                        use is less than 40      air emissions with
                                        tpy.                     PTE, with all exhaust
                                                                 gas streams being
                                                                 captured and routed to
                                                                 a control system.\5\
                                                                 Also,
                                                                ii. Continuously reduce
                                                                 EtO emissions by 80
                                                                 percent \1\ \5\.
                                       c. Initial startup is    i. Operate all areas of  Upon startup of the
                                        after April 5, 2024,     the facility that        source.
                                        and facility EtO use     contain Group 1 room
                                        is at least 40 tpy.      air emissions with
                                                                 PTE, with all exhaust
                                                                 gas streams being
                                                                 captured and routed to
                                                                 a control system.\4\
                                                                 Also,
                                                                ii. Continuously reduce
                                                                 EtO emissions by 98
                                                                 percent \1\ \4\.
                                       d. Initial startup is    i. Operate all areas of  Upon startup of the
                                        after April 5, 2024,     the facility that        source.
                                        and facility EtO use     contain Group 1 room
                                        is less than 40 tpy.     air emissions with
                                                                 PTE, with all exhaust
                                                                 gas streams being
                                                                 captured and routed to
                                                                 a control system.\5\
                                                                 Also,
                                                                ii. Continuously reduce
                                                                 EtO emissions by 80
                                                                 percent \1\ \5\.
----------------------------------------------------------------------------------------------------------------
\1\ If using CEMS to determine compliance, this standard is based on a rolling 30-operating day average.
\2\ The standard applies if the facility has met or exceeded the specified EtO use within any consecutive 12-
  month period after April 7, 2025.
\3\ The standard applies if the facility has used less than 40 tpy of EtO within all consecutive 12-month
  periods after April 6, 2026.
\4\ The standard applies if the facility is expected to meet or exceed the specified EtO use within one year
  after startup. Afterwards, the standard applies if the facility has met or exceeded the specified EtO use
  within any consecutive 12-month period after startup.
\5\ The standard applies if the facility is not expected to meet or exceed 40 tpy of EtO use within one year
  after startup. Afterwards, the standard applies if the facility has used less than 40 tpy of EtO within all
  consecutive 12-month periods after startup.


[[Page 24195]]

Table 5 to Subpart O of Part 63--Standards for Group 2 Room Air 
Emissions

    As required in Sec.  63.362(g), for your collection of Group 2 room 
air emissions, you must meet the applicable standard in the following 
table:

----------------------------------------------------------------------------------------------------------------
                                                                                           You must comply with
            For each . . .                 For which . . .           You must . . .       the requirement(s) . .
                                                                                                    .
----------------------------------------------------------------------------------------------------------------
1. Existing collection of Group 2      a. Not applicable......  i. Operate all areas of  No later than April 5,
 room air emissions at a major source                            the facility that        2027.
 facility.                                                       contain Group 2 room
                                                                 air emissions with
                                                                 PTE, with all exhaust
                                                                 gas streams being
                                                                 captured and routed to
                                                                 a control system.
                                                                 Also,
                                                                ii. Continuously reduce
                                                                 EtO emissions by 86
                                                                 percent \1\.
2. Existing collection of Group 2      a. Facility EtO use is   i. Operate all areas of  No later than April 6,
 room air emissions at an area source   at least 20 tpy.         the facility that        2026.
 facility.                                                       contain Group 2 room
                                                                 air emissions with
                                                                 PTE, with all exhaust
                                                                 gas streams being
                                                                 captured and routed to
                                                                 a control system.\2\
                                                                 Also,.
                                                                ii. Continuously reduce
                                                                 EtO emissions by 98
                                                                 percent \1\ \2\.
                                       b. Facility EtO use is   i. Operate all areas of  No later than April 6,
                                        at least 4 tpy but       the facility that        2026.
                                        less than 20 tpy.        contain Group 2 room
                                                                 air emissions with
                                                                 PTE, with all exhaust
                                                                 gas streams being
                                                                 captured and routed to
                                                                 a control system.\2\
                                                                 Also,
                                                                ii. Continuously reduce
                                                                 EtO emissions by 80
                                                                 percent \1\ \2\.
                                       c. Facility EtO use is   Lower the EtO            No later than April 5,
                                        less than 4 tpy.         concentration within     2027.
                                                                 each sterilization
                                                                 chamber to 1 ppm
                                                                 before the chamber can
                                                                 be opened \3\.
3. New collection of Group 2 room air  a. Initial startup is    i. Operate all areas of  No later than April 5,
 emissions at a major source facility.  on or before April 5,    the facility that        2024.
                                        2024.                    contain Group 2 room
                                                                 air emissions with
                                                                 PTE, with all exhaust
                                                                 gas streams being
                                                                 captured and routed to
                                                                 a control system.
                                                                 Also,
                                                                ii. Continuously reduce
                                                                 EtO emissions by 86
                                                                 percent \1\.
                                       b. Initial startup is    i. Operate all areas of  Upon startup of the
                                        after April 5, 2024.     the facility that        source.
                                                                 contain Group 2 room
                                                                 air emissions with
                                                                 PTE, with all exhaust
                                                                 gas streams being
                                                                 captured and routed to
                                                                 a control system.
                                                                 Also,
                                                                ii. Continuously reduce
                                                                 EtO emissions by 86
                                                                 percent \1\.
4. New collection of Group 2 room air  a. Initial startup is    i. Operate all areas of  No later than April 5,
 emissions at an area source facility.  on or before April 5,    the facility that        2024.
                                        2024, and facility EtO   contain Group 2 room
                                        use is at least 20 tpy.  air emissions with
                                                                 PTE, with all exhaust
                                                                 gas streams being
                                                                 captured and routed to
                                                                 a control system.\5\
                                                                 Also,
                                                                ii. Continuously reduce
                                                                 EtO emissions by 98
                                                                 percent \1\ \5\.
                                       b. Initial startup is    i. Operate all areas of  No later than April 5,
                                        on or before April 5,    the facility that        2024.
                                        2024, and facility EtO   contain Group 2 room
                                        use is less than 20      air emissions with
                                        tpy.                     PTE, with all exhaust
                                                                 gas streams being
                                                                 captured and routed to
                                                                 a control system.\6\
                                                                 Also,
                                                                ii. Continuously reduce
                                                                 EtO emissions by 80
                                                                 percent \1\ \6\.
                                       c. Initial startup is    i. Operate all areas of  Upon startup of the
                                        after April 5, 2024,     the facility that        source.
                                        and facility EtO use     contain Group 2 room
                                        is at least 20 tpy.      air emissions with
                                                                 PTE, with all exhaust
                                                                 gas streams being
                                                                 captured and routed to
                                                                 a control system.\5\
                                                                 Also,
                                                                ii. Continuously reduce
                                                                 EtO emissions by 98
                                                                 percent \1\ \5\.
                                       d. Initial startup is    i. Operate all areas of  Upon startup of the
                                        after April 5, 2024,     the facility that        source.
                                        and facility EtO use     contain Group 2 room
                                        is less than 20 tpy.     air emissions with
                                                                 PTE, with all exhaust
                                                                 gas streams being
                                                                 captured and routed to
                                                                 a control system.\6\
                                                                 Also,
                                                                ii. Continuously reduce
                                                                 EtO emissions by 80
                                                                 percent \1\ \6\.
----------------------------------------------------------------------------------------------------------------
\1\ This standard is based on a rolling 30-operating day average.
\2\ The standard applies if the facility has met or exceeded the specified EtO use within any consecutive 12-
  month period after April 7, 2025.
\3\ The standard applies if the facility has used less than 4 tpy of EtO within all consecutive 12-month periods
  after April 6, 2026.
\4\ The standard applies if the facility is expected to meet or exceed the specified EtO use within one year
  after startup. Afterwards, the standard applies if the facility has met or exceeded the specified EtO use
  within any consecutive 12-month period after startup.
\5\ The standard applies if the facility is not expected to meet or exceed 20 tpy of EtO use within one year
  after startup. Afterwards, the standard applies if the facility has used less than 20 tpy of EtO within all
  consecutive 12-month periods after startup.

Table 6 to Subpart O of Part 63--Applicability of General Provisions to 
This Subpart

    As specified in Sec.  63.360, the parts of the General Provisions 
that apply to you are shown in the following table:

------------------------------------------------------------------------
           Citation                Subject        Applies to subpart O
------------------------------------------------------------------------
Sec.   63.1(a)(1)............  Applicability..  Yes, additional terms
                                                 defined in Sec.
                                                 63.361; when overlap
                                                 between subparts A and
                                                 O occurs, subpart O
                                                 takes precedence.
Sec.   63.1(a)(2)-(3)........  ...............  Yes.
Sec.   63.1(a)(4)............  ...............  Yes. Subpart O clarifies
                                                 the applicability of
                                                 each paragraph in
                                                 subpart A to facilities
                                                 subject to subpart O.
Sec.   63.1(a)(5)............  [Reserved].....  No.
Sec.   63.1(a)(6)-(8)........  ...............  Yes.
Sec.   63.1(a)(9)............  [Reserved].....
Sec.   63.1(a)(10)-(14)......  ...............  Yes.
Sec.   63.1(b)(1)-(2)........  ...............  Yes.
Sec.   63.1(b)(3)............  ...............  No.
Sec.   63.1(c)(1)............  ...............  No. Subpart O clarifies
                                                 the applicability of
                                                 each paragraph in
                                                 subpart A to facilities
                                                 subject to subpart O in
                                                 this table.
Sec.   63.1(c)(2)............  ...............  Yes.

[[Page 24196]]

 
Sec.   63.1(c)(3)............  [Reserved].....  No.
Sec.   63.1(c)(4)............  ...............  Yes.
Sec.   63.1(c)(5)............  ...............  No. Sec.   63.360
                                                 specifies
                                                 applicability.
Sec.   63.1(c)(6)............  ...............  Yes.
Sec.   63.1(d)...............  [Reserved].....  No.
Sec.   63.1(e)...............  ...............  Yes.
Sec.   63.2..................  Definitions....  Yes, additional terms
                                                 defined in Sec.
                                                 63.361; when overlap
                                                 between subparts A and
                                                 O occurs, subpart O
                                                 takes precedence.
Sec.   63.3..................  Units and        Yes, other units used in
                                abbreviations.   subpart O are defined
                                                 in the text of subpart
                                                 O.
Sec.   63.4(a)(1)-(3)........  Prohibited       Yes.
                                activities.
Sec.   63.5(a)...............  Construction/    No. Sec.   63.366(b)(1)
                                Reconstruction.  contains applicability
                                                 requirements for
                                                 constructed or
                                                 reconstructed
                                                 facilities.
Sec.   63.5(b)(1)............  ...............  Yes.
Sec.   63.5(b)(2)............  [Reserved].....
Sec.   63.5(b)(3)............  ...............  No. See Sec.
                                                 63.366(b)(2).
Sec.   63.5(b)(4)-(6)........  ...............  Yes.
Sec.   63.5(c)...............  [Reserved].....
Sec.   63.5(d)(1)-(2)........  ...............  No. See Sec.
                                                 63.366(b)(3).
Sec.   63.5(d)(3)-(4)........  ...............  Yes.
Sec.   63.5(e)...............  ...............  Yes.
Sec.   63.5(f)(1)-(2)........  ...............  No. See Sec.
                                                 63.366(b)(4).
Sec.   63.6(a)...............  Applicability..  Yes.
Sec.   63.6(b)-(c)...........  ...............  No. Sec.   63.360(j)
                                                 specifies compliance
                                                 dates for facilities.
Sec.   63.6(d)...............  [Reserved].....
Sec.   63.6(e)(1)(i).........  ...............  No.
Sec.   63.6(e)(1)(ii)........  Requirement to   No.
                                correct
                                malfunctions
                                ASAP.
Sec.   63.6(e)(1)(iii).......  ...............  Yes.
Sec.   63.6(e)(2)............  [Reserved].....  No.
Sec.   63.6(e)(3)............  SSM Plan         No.
                                Requirements.
Sec.   63.6(f)(1)............  SSM exemption..  No.
Sec.   63.6(f)(2)(i).........  Methods for      Yes.
                                Determining
                                Compliance.
Sec.   63.6(f)(2)(ii)........  ...............  No. Sec.   63.363
                                                 specifies parameters
                                                 for determining
                                                 compliance.
Sec.   63.6(f)(2)(iii)-(iv)..  ...............  Yes.
Sec.   63.6(f)(2)(v).........  ...............  No.
Sec.   63.6(f)(3)............  ...............  Yes.
Sec.   63.6(g)...............  Alternative      Yes.
                                Standard.
Sec.   63.6(h)...............  Compliance with  No. Subpart O does not
                                opacity and      contain any opacity or
                                visible          visible emission
                                emission         standards.
                                standards.
Sec.   63.6(i)(1)-(14), and    Compliance       Yes.
 (16).                          Extension.
Sec.   63.6(j)...............  Presidential     Yes.
                                Compliance
                                Exemption.
Sec.   63.7(a)...............  Applicability    Yes.
                                and
                                Performance
                                Test Dates.
Sec.   63.7(b)...............  Notification of  Yes.
                                Performance
                                Test.
Sec.   63.7(c)...............  Quality          Yes.
                                Assurance/Test
                                Plan.
Sec.   63.7(d)...............  Testing          Yes.
                                Facilities.
Sec.   63.7(e)(1)............  SSM exemption..  No.
Sec.   63.7(e)(2)-(4)........  Conduct of       Yes. Sec.   63.365 also
                                Performance      contains test methods
                                Tests.           specific to facilities
                                                 subject to the
                                                 emissions standards.
Sec.   63.7(f)...............  Alternative      Yes.
                                Test Method.
Sec.   63.7(g)...............  Performance      Yes, except this subpart
                                Test Data        specifies how and when
                                Analysis.        the performance test
                                                 and performance
                                                 evaluation results are
                                                 reported.
Sec.   63.7(h)...............  Waiver of Tests  Yes.
Sec.   63.8(a)(1)............  Applicability    Yes.
                                of Monitoring
                                Requirements.
Sec.   63.8(a)(2)............  Performance      Yes.
                                Specifications.
Sec.   63.8(a)(3)............  [Reserved].....  No.
Sec.   63.8(a)(4)............  Monitoring with  Yes.
                                Flares.
Sec.   63.8(b)(1)............  Monitoring.....  Yes.
Sec.   63.8(b)(2)-(3)........  Multiple         Yes.
                                Effluents and
                                Multiple
                                Monitoring
                                Systems.
Sec.   63.8(c)(1)(i).........  General duty to  No.
                                minimize
                                emissions and
                                CMS operation.
Sec.   63.8(c)(1)(ii)........  ...............  No. A startup, shutdown,
                                                 and malfunction plan is
                                                 not required for these
                                                 standards.
Sec.   63.8(c)(1)(iii).......  Requirement to   No.
                                develop SSM
                                Plan for CMS.
Sec.   63.8(c)(2)-(3)........  ...............  Yes.
Sec.   63.8(c)(4)-(5)........  ...............  No. Frequency of
                                                 monitoring measurements
                                                 is provided in Sec.
                                                 63.364; opacity
                                                 monitors are not
                                                 required for these
                                                 standards.
Sec.   63.8(c)(6)............  ...............  No. Performance
                                                 specifications are
                                                 contained in Sec.
                                                 63.365.

[[Page 24197]]

 
Sec.   63.8(c)(7)(i)(A)-(B)..  ...............  No. Performance
                                                 specifications are
                                                 contained in Sec.
                                                 63.365.
Sec.   63.8(c)(7)(i)(C)......  ...............  No. Opacity monitors are
                                                 not required for these
                                                 standards.
Sec.   63.8(c)(7)(ii)........  ...............  No. Performance
                                                 specifications are
                                                 contained in Sec.
                                                 63.365.
Sec.   63.8(c)(8)............  ...............  No.
Sec.   63.8(d)(1)-(2)........  ...............  Yes.
Sec.   63.8(d)(3)............  Written          No.
                                procedures for
                                CMS.
Sec.   63.8(e)(1)............  CMS Performance  Yes, but only applies
                                Evaluation.      for CEMS, except this
                                                 subpart specifies how
                                                 and when the
                                                 performance evaluation
                                                 results are reported.
Sec.   63.8(e)(2)............  ...............  Yes.
Sec.   63.8(e)(3)............  ...............  Yes.
Sec.   63.8(e)(4)............  ...............  Yes.
Sec.   63.8(e)(5)(i).........  ...............  Yes.
Sec.   63.8(e)(5)(ii)........  ...............  No. Opacity monitors are
                                                 not required for these
                                                 standards.
Sec.   63.8(f)(1)-(5)........  ...............  Yes.
Sec.   63.8(f)(6)............  ...............  No.
Sec.   63.8(g)(1)............  ...............  Yes.
Sec.   63.8(g)(2)............  ...............  No.
Sec.   63.8(g)(3)-(5)........  ...............  Yes.
Sec.   63.9(a)...............  Notification     Yes.
                                requirements.
Sec.   63.9(b)(1)-(i)........  ...............  Yes.
Sec.   63.9(b)(1)(ii)-(iii)..  Initial          No. Sec.
                                Notifications.   63.366(c)(1)(i)
                                                 contains language for
                                                 facilities that
                                                 increase usage such
                                                 that the source becomes
                                                 subject to the
                                                 emissions standards.
Sec.   63.9(b)(2)-(3)........  Initial          Yes. Sec.   63.366(c)(3)
                                Notifications.   contains additional
                                                 information to be
                                                 included in the initial
                                                 report for existing and
                                                 new facilities.
Sec.   63.9(b)(4)-(5)........  Initial          No. Sec.
                                Notifications.   63.366(c)(1)(ii) and
                                                 (iii) contains
                                                 requirements for new or
                                                 reconstructed
                                                 facilities subject to
                                                 the emissions
                                                 standards.
Sec.   63.9(c)...............  Request for      Yes.
                                Compliance
                                Extension.
Sec.   63.9(d)...............  Notification of  No.
                                Special
                                Compliance
                                Requirements
                                for New
                                Sources.
Sec.   63.9(e)...............  Notification of  Yes.
                                Performance
                                Test.
Sec.   63.9(f)...............  Notification of  No. Opacity monitors are
                                VE/Opacity       not required for these
                                Test.            standards.
Sec.   63.9(g)(1)............  Additional       Yes.
                                Notifications
                                When Using CMS.
Sec.   63.9(g)(2)-(3)........  Additional       No. Opacity monitors and
                                Notifications    relative accuracy
                                When Using CMS.  testing are not
                                                 required for these
                                                 standards.
Sec.   63.9(h)(1)-(3)........  Notification of  Yes, except Sec.
                                Compliance       63.9(h)(5) does not
                                Status.          apply because Sec.
                                                 63.366(c)(2) instructs
                                                 facilities to submit
                                                 actual data.
Sec.   63.9(i)...............  Adjustment of    Yes.
                                Submittal
                                Deadlines.
Sec.   63.9(j)...............  Change in        Yes.
                                previous
                                information.
Sec.   63.9(k)...............  Electronic       Yes, as specified in
                                reporting        Sec.   63.9(j).
                                procedures.
Sec.   63.10(a)..............  Recordkeeping/   Yes.
                                Reporting.
Sec.   63.10(b)(1)...........  Recordkeeping/   Yes.
                                Reporting.
Sec.   63.10(b)(2)(i)........  Recordkeeping    No. See 63.367(f) for
                                for startup      recordkeeping
                                and shutdown.    requirements.
Sec.   63.10(b)(2)(ii).......  Recordkeeping    No. See 63.367(f) for
                                for SSM and      recordkeeping
                                failures to      requirements.
                                meet standards.
Sec.   63.10(b)(2)(iii)......  Records related  Yes.
                                to maintenance
                                of air
                                pollution
                                control
                                equipment.
Sec.   63.10(b)(2)(iv)-(v)...  Actions taken    No.
                                to minimize
                                emissions
                                during SSM.
Sec.   63.10(b)(2)(vi).......  CMS Records....  Yes.
Sec.   63.10(b)(2)(vii)-(ix).  Records........  Yes.
Sec.   63.10(b)(2)(x)-(xi)...  CMS Records....  Yes.
Sec.   63.10(b)(2)(xii)......  Records........  Yes.
Sec.   63.10(b)(2)(xiii).....  Records........  Yes.
Sec.   63.10(b)(2)(xiv)......  Records........  Yes.
Sec.   63.10(b)(3)...........  Records........  Yes.
Sec.   63.10(c)(1)-(14)......  Records........  Yes.
Sec.   63.10(c)(15)..........  Use of SSM Plan  No.
Sec.   63.10(d)(1)...........  General          Yes.
                                Reporting
                                Requirements.
Sec.   63.10(d)(2)...........  Report of        No. This subpart
                                Performance      specifies how and when
                                Test Results.    the performance test
                                                 results are reported.
Sec.   63.10(d)(3)...........  Reporting        No. Subpart O does not
                                Opacity or VE    contain opacity or
                                Observations.    visible emissions
                                                 standards.
Sec.   63.10(d)(4)...........  Progress         Yes.
                                Reports.
Sec.   63.10(d)(5)...........  SSM Reports....  No. See Sec.   63.366
                                                 for malfunction
                                                 reporting requirements.
Sec.   63.10(e)(1)...........  Additional CEMS  Yes.
                                Reports.

[[Page 24198]]

 
Sec.   63.10(e)(2)(i)........  Additional CMS   Yes, except this subpart
                                Reports.         specifies how and when
                                                 the performance
                                                 evaluation results are
                                                 reported.
Sec.   63.10(e)(2)(ii).......  Additional COMS  No. Opacity monitors are
                                Reports.         not required for these
                                                 standards.
Sec.   63.10(e)(3)(i)-(iv)...  Reports........  Yes.
Sec.   63.10(e)(3)(v)........  Excess           No. Sec.   63.366(b) and
                                Emissions        (c) specify contents
                                Reports.         and submittal dates for
                                                 excess emissions and
                                                 monitoring system
                                                 performance reports.
Sec.   63.10(e)(3)(vi)-(viii)  Excess           Yes.
                                Emissions
                                Report and
                                Summary Report.
Sec.   63.10(e)(4)...........  Reporting COMS   No. Opacity monitors are
                                data.            not required for these
                                                 standards.
Sec.   63.10(f)..............  Waiver for       Yes.
                                Recordkeeping/
                                Reporting.
Sec.   63.11.................  Control device   Yes.
                                requirements
                                for flares and
                                work practice
                                requirements
                                for equipment
                                leaks.
Sec.   63.12.................  Delegation.....  Yes.
Sec.   63.13.................  Addresses......  Yes.
Sec.   63.14.................  Incorporation    Yes.
                                by Reference.
Sec.   63.15.................  Availability of  Yes.
                                Information.
------------------------------------------------------------------------

Appendix A to Subpart O of Part 63--Monitoring Provisions for EtO CEMS

1. Applicability

    These monitoring provisions apply to the measurement of EtO 
emissions from commercial sterilization facilities, using CEMS. The 
CEMS must be capable of measuring EtO in lb/hr.

2. Monitoring of EtO Emissions

    2.1 Monitoring System Installation Requirements. Install EtO 
CEMS and any additional monitoring systems needed to convert 
pollutant concentrations to lb/hr in accordance with Sec.  63.365 
and Performance Specification 19 (PS 19) of appendix B to part 60 of 
this chapter.
    2.2 Primary and Backup Monitoring Systems. In the electronic 
monitoring plan described in section 10.1.1.2.1 of this appendix, 
you must designate a primary EtO CEMS. The primary EtO CEMS must be 
used to report hourly EtO concentration values when the system is 
able to provide quality-assured data, i.e., when the system is ``in 
control''. However, to increase data availability in the event of a 
primary monitoring system outage, you may install, operate, 
maintain, and calibrate backup monitoring systems, as follows:
    2.2.1 Redundant Backup Systems. A redundant backup monitoring 
system is a separate EtO CEMS with its own probe, sample interface, 
and analyzer. A redundant backup system is one that is permanently 
installed at the unit or stack location and is kept on ``hot 
standby'' in case the primary monitoring system is unable to provide 
quality-assured data. A redundant backup system must be represented 
as a unique monitoring system in the electronic monitoring plan. 
Each redundant backup monitoring system must be certified according 
to the applicable provisions in section 3 of this appendix and must 
meet the applicable on-going QA requirements in section 5 of this 
appendix.
    2.2.2 Non-redundant Backup Monitoring Systems. A non-redundant 
backup monitoring system is a separate EtO CEMS that has been 
certified at a particular unit or stack location but is not 
permanently installed at that location. Rather, the system is kept 
on ``cold standby'' and may be reinstalled in the event of a primary 
monitoring system outage. A nonredundant backup monitoring system 
must be represented as a unique monitoring system in the electronic 
monitoring plan. Non-redundant backup EtO CEMS must complete the 
same certification tests as the primary monitoring system, with one 
exception. The 7-day calibration error test is not required for a 
non-redundant backup EtO CEMS. Except as otherwise provided in 
section 2.2.4.4 of this appendix, a non-redundant backup monitoring 
system may only be used for 720 hours per year at a particular unit 
or stack location.
    2.2.3 Temporary Like-kind Replacement Analyzers. When a primary 
EtO analyzer needs repair or maintenance, you may temporarily 
install a like-kind replacement analyzer, to minimize data loss. 
Except as otherwise provided in section 2.2.4.4 of this appendix, a 
temporary like-kind replacement analyzer may only be used for 720 
hours per year at a particular unit or stack location. The analyzer 
must be represented as a component of the primary EtO CEMS and must 
be assigned a 3-character component ID number, beginning with the 
prefix ``LK''.
    2.2.4 Quality Assurance Requirements for Non-redundant Backup 
Monitoring Systems and Temporary Like-kind Replacement Analyzers. To 
quality-assure the data from non-redundant backup EtO monitoring 
systems and temporary like-kind replacement EtO analyzers, the 
following provisions apply:
    2.2.4.1 When a certified non-redundant backup EtO CEMS or a 
temporary like-kind replacement EtO analyzer is brought into 
service, a calibration error test and a linearity check must be 
performed and passed. A single point system integrity check is also 
required.
    2.2.4.2 Each non-redundant backup EtO CEMS or temporary like-
kind replacement EtO analyzer shall comply with all required daily, 
weekly, and quarterly quality-assurance test requirements in section 
5 of this appendix, for as long as the system or analyzer remains in 
service.
    2.2.4.3 For the routine, on-going quality-assurance of a non-
redundant backup EtO monitoring system, a relative accuracy test 
audit (RATA) must be performed and passed at least once every 8 
calendar quarters at the unit or stack location(s) where the system 
will be used.
    2.2.4.4 To use a non-redundant backup EtO monitoring system or a 
temporary like-kind replacement analyzer for more than 720 hours per 
year at a particular unit or stack location, a RATA must first be 
performed and passed at that location.
    2.3 Monitoring System Equipment, Supplies, Definitions, and 
General Operation.
    The following provisions apply:
    2.3.1 PS 19, Sections 3.0, 6.0, and 11.0 of appendix B to part 
60 of this chapter.

3. Initial Certification Procedures

    The initial certification procedures for the EtO CEMS used to 
provide data under this subpart are as follows:
    3.1 Your EtO CEMS must be certified according to PS 19, 
section(s) 13.
    3.2 Any additional stack gas flow rate monitoring system(s) 
needed to express pollutant concentrations in lb/hr must be 
certified according to part 75 of this chapter.

4. Recertification Procedures

    Whenever the owner or operator makes a replacement, 
modification, or change to a certified CEMS that may significantly 
affect the ability of the system to accurately measure or record 
pollutant gas concentrations or stack gas flow rates, the owner or 
operator shall recertify the monitoring system. Furthermore, 
whenever the owner or operator makes a replacement, modification, or 
change to the flue gas handling system or the unit operation that 
may significantly change the concentration or flow profile, the 
owner or operator shall recertify the monitoring system. The same 
tests performed for the initial certification of the monitoring 
system shall be repeated for recertification, unless otherwise 
specified by the Administrator. Examples of changes that require 
recertification include: Replacement of a gas analyzer; complete 
monitoring

[[Page 24199]]

system replacement, and changing the location or orientation of the 
sampling probe.

5. On-Going Quality Assurance Requirements

    On-going QA test requirements for EtO CEMS must be implemented 
as follows:
    5.1 The quality assurance/quality control procedures in 
Procedure 7 of appendix F to part 60 of this chapter shall apply.
    5.2 Stack gas flow rate, diluent gas, and moisture monitoring 
systems must meet the applicable ongoing QA test requirements of 
part 75 of this chapter.
    5.2.1 Out-of-Control Periods. A EtO CEMS that is used to provide 
data under this appendix is considered to be out-of-control, and 
data from the CEMS may not be reported as quality-assured, when any 
acceptance criteria for a required QA test is not met. The EtO CEMS 
is also considered to be out-of-control when a required QA test is 
not performed on schedule or within an allotted grace period. To end 
an out-of-control period, the QA test that was either failed or not 
done on time must be performed and passed. Out-of-control periods 
are counted as hours of monitoring system downtime.
    5.2.2 Grace Periods. For the purposes of this appendix, a 
``grace period'' is defined as a specified number of unit or stack 
operating hours after the deadline for a required quality-assurance 
test of a continuous monitor has passed, in which the test may be 
performed and passed without loss of data.
    5.2.2.1 For the flow rate monitoring systems described in 
section 5.1 of this appendix, a 168 unit or stack operating hour 
grace period is available for quarterly linearity checks, and a 720 
unit or stack operating hour grace period is available for RATAs, as 
provided, respectively, in sections 2.2.4 and 2.3.3 of appendix B to 
part 75 of this chapter.
    5.2.2.2 For the purposes of this appendix, if the deadline for a 
required gas audit or RATA of a EtO CEMS cannot be met due to 
circumstances beyond the control of the owner or operator:
    5.2.2.2.1 A 168 unit or stack operating hour grace period is 
available in which to perform the gas audit; or
    5.2.2.2.2 A 720 unit or stack operating hour grace period is 
available in which to perform the RATA.
    5.2.2.3 If a required QA test is performed during a grace 
period, the deadline for the next test shall be determined as 
follows:
    5.2.2.3.1 For the gas audit of an EtO CEMS, the grace period 
test only satisfies the audit requirement for the calendar quarter 
in which the test was originally due. If the calendar quarter in 
which the grace period audit is performed is a QA operating quarter, 
an additional gas audit is required for that quarter.
    5.2.2.3.2 For the RATA of an EtO CEMS, the next RATA is due 
within three QA operating quarters after the calendar quarter in 
which the grace period test is performed.
    5.2.3 Conditional Data Validation. For recertification and 
diagnostic testing of the monitoring systems that are used to 
provide data under this appendix, and for the required QA tests when 
nonredundant backup monitoring systems or temporary like-kind 
replacement analyzers are brought into service, the conditional data 
validation provisions in Sec. Sec.  75.20(b)(3)(ii) through 
(b)(3)(ix) of this chapter may be used to avoid or minimize data 
loss. The allotted window of time to complete calibration tests and 
RATAs shall be as specified in Sec.  75.20(b)(3)(iv) of this 
chapter; the allotted window of time to complete a gas audit shall 
be the same as for a linearity check (i.e., 168 unit or stack 
operating hours).
    5.3 Data Validation.
    5.3.1 Out-of-Control Periods. An EtO CEMS that is used to 
provide data under this appendix is considered to be out-of-control, 
and data from the CEMS may not be reported as quality-assured, when 
any acceptance criteria for a required QA test is not met. The EtO 
CEMS is also considered to be out-of-control when a required QA test 
is not performed on schedule or within an allotted grace period. To 
end an out-of-control period, the QA test that was either failed or 
not done on time must be performed and passed. Out-of-control 
periods are counted as hours of monitoring system downtime.
    5.3.2 Grace Periods. For the purposes of this appendix, a 
``grace period'' is defined as a specified number of unit or stack 
operating hours after the deadline for a required quality-assurance 
test of a continuous monitor has passed, in which the test may be 
performed and passed without loss of data.
    5.3.2.1 For the monitoring systems described in section 5.1 of 
this appendix, a 168 unit or stack operating hour grace period is 
available for quarterly linearity checks, and a 720 unit or stack 
operating hour grace period is available for RATAs, as provided, 
respectively, in sections 2.2.4 and 2.3.3 of appendix B to part 75 
of this chapter.
    5.3.2.2 For the purposes of this appendix, if the deadline for a 
required gas audit/data accuracy assessment or RATA of an EtO CEMS 
cannot be met due to circumstances beyond the control of the owner 
or operator:
    5.3.2.2.1 A 168 unit or stack operating hour grace period is 
available in which to perform the gas audit or other quarterly data 
accuracy assessment; or
    5.3.2.2.2 A 720 unit or stack operating hour grace period is 
available in which to perform the RATA.
    5.3.2.3 If a required QA test is performed during a grace 
period, the deadline for the next test shall be determined as 
follows:
    5.3.2.3.1 For a gas audit or RATA of the monitoring systems 
described in sections 5.1 and 5.2 of this appendix, determine the 
deadline for the next gas audit or RATA (as applicable) in 
accordance with section 2.2.4(b) or 2.3.3(d) of appendix B to part 
75 of this chapter; treat a gas audit in the same manner as a 
linearity check.
    5.3.2.3.2 For the gas audit or other quarterly data accuracy 
assessment of an EtO CEMS, the grace period test only satisfies the 
audit requirement for the calendar quarter in which the test was 
originally due. If the calendar quarter in which the grace period 
audit is performed is a QA operating quarter, an additional gas 
audit/data accuracy assessment is required for that quarter.
    5.3.2.3.3 For the RATA of an EtO CEMS, the next RATA is due 
within three QA operating quarters after the calendar quarter in 
which the grace period test is performed.
    5.3.3 Conditional Data Validation. For recertification and 
diagnostic testing of the monitoring systems that are used to 
provide data under this appendix, the conditional data validation 
provisions in Sec.  75.20(b)(3)(ii) through (ix) of this chapter may 
be used to avoid or minimize data loss. The allotted window of time 
to complete calibration tests and RATAs shall be as specified in 
Sec.  75.20(b)(3)(iv) of this chapter; the allotted window of time 
to complete a quarterly gas audit or data accuracy assessment shall 
be the same as for a linearity check (i.e., 168 unit or stack 
operating hours).

6. Missing Data Requirements

    For the purposes of this appendix, the owner or operator of an 
affected unit shall not substitute for missing data from EtO CEMS. 
Any process operating hour for which quality-assured EtO 
concentration data are not obtained is counted as an hour of 
monitoring system downtime.

7. Bias Adjustment

    Bias adjustment of hourly emissions data from an EtO CEMS is not 
required.

8. QA/QC Program Requirements

    The owner or operator shall develop and implement a quality 
assurance/quality control (QA/QC) program for the EtO CEMS that are 
used to provide data under this subpart. At a minimum, the program 
shall include a written plan that describes in detail (or that 
refers to separate documents containing) complete, step-by-step 
procedures and operations for the most important QA/QC activities. 
Electronic storage of the QA/QC plan is permissible, provided that 
the information can be made available in hard copy to auditors and 
inspectors. The QA/QC program requirements for the other monitoring 
systems described in section 5.2 of this appendix are specified in 
section 1 of appendix B to part 75 of this chapter.
    8.1 General Requirements for EtO CEMS.
    8.1.1 Preventive Maintenance. Keep a written record of 
procedures needed to maintain the EtO CEMS in proper operating 
condition and a schedule for those procedures. This shall, at a 
minimum, include procedures specified by the manufacturers of the 
equipment and, if applicable, additional or alternate procedures 
developed for the equipment.
    8.1.2 Recordkeeping and Reporting. Keep a written record 
describing procedures that will be used to implement the 
recordkeeping and reporting requirements of this appendix.
    8.1.3 Maintenance Records. Keep a record of all testing, 
maintenance, or repair activities performed on any EtO CEMS in a 
location and format suitable for inspection. A maintenance log may 
be used for this purpose. The following records should be 
maintained: Date, time, and description of any testing, adjustment, 
repair, replacement, or preventive maintenance action performed on 
any monitoring system and records of any corrective actions 
associated with a monitor outage period. Additionally, any 
adjustment that may significantly affect a system's ability to 
accurately measure emissions data must be recorded and a written 
explanation of the

[[Page 24200]]

procedures used to make the adjustment(s) shall be kept.
    8.2 Specific Requirements for EtO CEMS. The following 
requirements are specific to EtO CEMS:
    8.2.1 Keep a written record of the procedures used for each type 
of QA test required for each EtO CEMS. Explain how the results of 
each type of QA test are calculated and evaluated.
    8.2.2 Explain how each component of the EtO CEMS will be 
adjusted to provide correct responses to calibration gases after 
routine maintenance, repairs, or corrective actions.

9. Data Reduction and Calculations

    9.1 Design and operate the EtO CEMS to complete a minimum of one 
cycle of operation (sampling, analyzing, and data recording) for 
each successive 15-minute period.
    9.2 Reduce the EtO concentration data to hourly averages in 
accordance with Sec.  60.13(h)(2) of this chapter.
    9.3 Convert each hourly average EtO concentration to an EtO mass 
emission rate (lb/hr) using an equation that has the general form of 
equation A-1 of this appendix:
[GRAPHIC] [TIFF OMITTED] TR05AP24.045

Where:

Eho = EtO mass emission rate for the hour, lb/hr
K = Units conversion constant, 1.144E-10 lb/scf-ppbv,
Ch = Hourly average EtO concentration, ppbv,
Qh = Stack gas volumetric flow rate for the hour, scfh.

    (Note: Use unadjusted flow rate values; bias adjustment is not 
required.)
    9.4 Use equation A-2 of this appendix to calculate the daily 
total EtO emissions. Report each daily total to the same precision 
as the most stringent standard that applies to any affected source 
exhausting to the emission stream (e.g., if the emission stream 
includes contributions from an SCV and ARV subject to 99.99% and 
99.9% emission reduction standards, respectively, report to four 
significant figures), expressed in scientific notation.
[GRAPHIC] [TIFF OMITTED] TR05AP24.046

Where:

    Eday = Total daily EtO emissions, lb.
    Eho = Hourly EtO emission rate for unit or stack 
sampling hour ``h'' in the averaging period, from equation A-1 of 
this appendix, lb/hr.
    9.5 Use equation A-3 of this appendix to calculate the 30-
operating day rolling total EtO emissions. Report each 30-operating 
day rolling total to the same precision as the most stringent 
standard that applies to any affected source exhausting to the 
emission stream (e.g., if the emission stream includes contributions 
from an SCV and ARV subject to 99.99% and 99.9% emission reduction 
standards, respectively, report to four significant figures), 
expressed in scientific notation.
[GRAPHIC] [TIFF OMITTED] TR05AP24.047

Where:

    E30day = Total EtO emissions during the 30-operating 
day, lb.
    Eday,i = Total daily EtO emissions, in lbs, for each 
operating day i from equation A-2 of this appendix, lb.
    i = Operating day index.

10. Recordkeeping Requirements

    10.1 For each EtO CEMS installed at an affected source, and for 
any other monitoring system(s) needed to convert pollutant 
concentrations to units of the applicable emissions limit, the owner 
or operator must maintain a file of all measurements, data, reports, 
and other information required by this appendix in a form suitable 
for inspection, for 5 years from the date of each record, in 
accordance with Sec.  63.367. The file shall contain the information 
in paragraphs 10.1.1 through 10.1.8 of this section.
    10.1.1 Monitoring Plan Records. For each affected source or 
group of sources monitored at a common stack, the owner or operator 
shall prepare and maintain a monitoring plan for the EtO CEMS and 
any other monitoring system(s) (i.e., flow rate, diluent gas, or 
moisture systems) needed to convert pollutant concentrations to 
units of the applicable emission standard. The monitoring plan shall 
contain essential information on the continuous monitoring systems 
and shall explain how the data derived from these systems ensure 
that all EtO emissions from the unit or stack are monitored and 
reported.
    10.1.1.1 Updates. Whenever the owner or operator makes a 
replacement, modification, or change in a certified continuous EtO 
monitoring system that is used to provide data under this subpart 
(including a change in the automated data acquisition and handling 
system or the flue gas handling system) which affects information 
reported in the monitoring plan (e.g., a change to a serial number 
for a component of a monitoring system), the owner or operator shall 
update the monitoring plan.
    10.1.1.2 Contents of the Monitoring Plan. For EtO CEMS, the 
monitoring plan shall contain the applicable electronic and hard 
copy information in sections 10.1.1.2.1 and 10.1.1.2.2 of this 
appendix. For stack gas flow rate, diluent gas, and moisture 
monitoring systems, the monitoring plan shall include the electronic 
and hard copy information required for those systems under Sec.  
75.53(g) of this chapter. The electronic monitoring plan shall be 
evaluated using CEDRI.
    10.1.1.2.1 Electronic. Record the unit or stack ID number(s); 
monitoring location(s); the EtO monitoring methodology used (i.e., 
CEMS); EtO monitoring system information, including, but not limited 
to: unique system and component ID numbers; the make, model, and 
serial number of the monitoring equipment; the sample acquisition 
method; formulas used to calculate emissions; monitor span and range 
information (if applicable).
    10.1.1.2.2 Hard Copy. Keep records of the following: schematics 
and/or blueprints showing the location of the monitoring system(s) 
and test ports; data flow diagrams; test protocols; monitor span and 
range calculations (if applicable); miscellaneous technical 
justifications.
    10.1.2 EtO Emissions Records. For EtO CEMS, the owner or 
operator must record the following information for each unit or 
stack operating hour:
    10.1.2.1 The date and hour;
    10.1.2.2 Monitoring system and component identification codes, 
as provided in the electronic monitoring plan, for each hour in 
which the CEMS provides a quality-assured value of EtO concentration 
(as applicable);
    10.1.2.3 The pollutant concentration, for each hour in which a 
quality-assured value is obtained. Record the data in parts per 
billion by volume (ppbv), with one leading non-zero digit and one 
decimal place, expressed in scientific notation. Use the following 
rounding convention: If the digit immediately following the first 
decimal place

[[Page 24201]]

is 5 or greater, round the first decimal place upward (increase it 
by one); if the digit immediately following the first decimal place 
is 4 or less, leave the first decimal place unchanged.
    10.1.2.4 A special code, indicating whether or not a quality-
assured EtO concentration value is obtained for the hour. This code 
may be entered manually when a temporary like-kind replacement EtO 
analyzer is used for reporting; and
    10.1.2.5 Monitor data availability, as a percentage of unit or 
stack operating hours, calculated according to Sec.  75.32 of this 
chapter.
    10.1.3 Stack Gas Volumetric Flow Rate Records.
    10.1.3.1 Hourly measurements of stack gas volumetric flow rate 
during unit operation are required to demonstrate compliance with 
EtO emission standards.
    10.1.3.2 Use a flow rate monitor that meets the requirements of 
part 75 of this chapter to record the required data. You must keep 
hourly flow rate records, as specified in Sec.  75.57(c)(2) of this 
chapter.
    10.1.4 EtO Emission Rate Records. Record the following 
information for each affected unit or common stack:
    10.1.4.1 The date and hour;
    10.1.4.2 The hourly EtO emissions rate (lb/hr), for each hour in 
which valid values of EtO concentration and stack gas volumetric 
flow rate are obtained for the hour. Report each emission rate to 
the same precision as the most stringent standard that applies to 
any affected source exhausting to the emission stream (e.g., if the 
emission stream includes contributions from an SCV and ARV subject 
to 99.99% and 99.9% emission reduction standards, respectively, 
report to four significant figures), expressed in scientific 
notation. Use the following rounding convention: If the digit 
immediately following the first decimal place is 5 or greater, round 
the first decimal place upward (increase it by one); if the digit 
immediately following the first decimal place is 4 or less, leave 
the first decimal place unchanged;
    10.1.4.4 A code indicating that the EtO emission rate was not 
calculated for the hour, if valid data for EtO concentration and/or 
any of the other necessary parameters are not obtained for the hour. 
For the purposes of this appendix, the substitute data values 
required under part 75 of this chapter for stack gas flow rate are 
not considered to be valid data.
    10.1.5 Certification and Quality Assurance Test Records. For the 
EtO CEMS used to provide data under this subpart at each affected 
unit (or group of units monitored at a common stack), record the 
following information for all required certification, 
recertification, diagnostic, and quality-assurance tests:
    10.1.5.1 EtO CEMS.
    10.1.5.1.1 For each required 7-day and daily calibration drift 
(CD) test or daily calibration error test (including daily 
calibration transfer standard tests) of the EtO CEMS, record the 
test date(s) and time(s), reference gas value(s), monitor 
response(s), and calculated calibration drift or calibration error 
value(s). If you use the dynamic spiking option for the mid-level 
calibration drift check under PS 19, you must also record the 
measured concentration of the native EtO in the flue gas before and 
after the spike and the spiked gas dilution factor.
    10.1.5.1.2 or each required RATA of an EtO CEMS, record the 
beginning and ending date and time of each test run, the reference 
method(s) used, and the reference method and EtO CEMS run values. 
Keep records of stratification tests performed (if any), all of the 
raw field data, relevant process operating data, and all of the 
calculations used to determine the relative accuracy.
    10.1.5.1.3 For each required measurement error (ME) test of an 
EtO monitor, record the date and time of each gas injection, the 
reference gas concentration (low, mid, or high) and the monitor 
response for each of the three injections at each of the three 
levels. Also record the average monitor response and the ME at each 
gas level and the related calculations.
    10.1.5.1.4 For each required level of detection (LOD) test of an 
EtO monitor performed in a controlled environment, record the test 
date, the concentrations of the reference gas and interference 
gases, the results of the seven (or more) consecutive measurements 
of EtO, the standard deviation, and the LOD value. For each required 
LOD test performed in the field, record the test date, the three 
measurements of the native source EtO concentration, the results of 
the three independent standard addition (SA) measurements known as 
standard addition response (SAR), the effective spike addition gas 
concentration, the resulting standard addition detection level 
(SADL) value and all related calculations. For extractive CEMS 
performing the SA using dynamic spiking, you must record the spiked 
gas dilution factor.
    10.1.5.1.5 For each required ME/level of detection response time 
test of an EtO monitor, record the test date, the native EtO 
concentration of the flue gas, the reference gas value, the stable 
reference gas readings, the upscale/downscale start and end times, 
and the results of the upscale and downscale stages of the test.
    10.1.5.1.6 For each required interference test of an EtO 
monitor, record (or obtain from the analyzer manufacturer records 
of): The date of the test; the gas volume/rate, temperature, and 
pressure used to conduct the test; the EtO concentration of the 
reference gas used; the concentrations of the interference test 
gases; the baseline EtO responses for each interferent combination 
spiked; and the total percent interference as a function of span or 
EtO concentration.
    10.1.5.1.7 For each quarterly relative accuracy audit (RAA) of 
an EtO monitor, record the beginning and ending date and time of 
each test run, the reference method used, the EtO concentrations 
measured by the reference method and CEMS for each test run, the 
average concentrations measured by the reference method and the 
CEMS, and the calculated relative accuracy. Keep records of the raw 
field data, relevant process operating data, and the calculations 
used to determine the relative accuracy.
    10.1.5.1.8 For each quarterly cylinder gas audit (CGA) of an EtO 
monitor, record the date and time of each injection, and the 
reference gas concentration (zero, mid, or high) and the monitor 
response for each injection. Also record the average monitor 
response and the calculated ME at each gas level.
    10.1.5.1.9 For each quarterly dynamic spiking audit (DSA) of an 
EtO monitor, record the date and time of the zero gas injection and 
each spike injection, the results of the zero gas injection, the gas 
concentrations (mid and high) and the dilution factors and the 
monitor response for each of the six upscale injections as well as 
the corresponding native EtO concentrations measured before and 
after each injection. Also record the average dynamic spiking error 
for each of the upscale gases, the calculated average DSA Accuracy 
at each upscale gas concentration, and all calculations leading to 
the DSA Accuracy.
    10.1.5.2 Additional Monitoring Systems. For the stack gas flow 
rate monitoring systems described in section 3.2 of this appendix, 
you must keep records of all certification, recertification, 
diagnostic, and on-going quality-assurance tests of these systems, 
as specified in Sec.  75.59(a) of this chapter.

11. Reporting Requirements

    11.1 General Reporting Provisions. The owner or operator shall 
comply with the following requirements for reporting EtO emissions 
from each affected unit (or group of units monitored at a common 
stack):
    11.1.1 Notifications, in accordance with paragraph 11.2 of this 
section;
    11.1.2 Monitoring plan reporting, in accordance with paragraph 
11.3 of this section;
    11.1.3 Certification, recertification, and QA test submittals, 
in accordance with paragraph 11.4 of this section; and
    11.1.4 Electronic quarterly report submittals, in accordance 
with paragraph 11.5 of this section.
    11.2 Notifications. The owner or operator shall provide 
notifications for each affected unit (or group of units monitored at 
a common stack) in accordance with Sec.  63.366.
    11.3 Monitoring Plan Reporting. For each affected unit (or group 
of units monitored at a common stack) using EtO CEMS, the owner or 
operator shall make electronic and hard copy monitoring plan 
submittals as follows:
    11.3.1 For a sterilization facility that begins reporting hourly 
EtO concentrations with a previously certified CEMS, submit the 
monitoring plan information in section 10.1.1.2 of this appendix 
prior to or concurrent with the first required quarterly emissions 
report. For a new sterilization facility, submit the information in 
section 10.1.1.2 of this appendix at least 21 days prior to the 
start of initial certification testing of the CEMS. Also submit the 
monitoring plan information in Sec.  75.53(g) of this chapter 
pertaining to any required flow rate monitoring systems within the 
applicable timeframe specified in this section, if the required 
records are not already in place.
    11.3.2 Update the monitoring plan when required, as provided in 
paragraph 10.1.1.1 of this appendix. An electronic monitoring plan 
information update must be submitted either

[[Page 24202]]

prior to or concurrent with the quarterly report for the calendar 
quarter in which the update is required.
    11.3.3 All electronic monitoring plan submittals and updates 
shall be made to the Administrator using CEDRI. Hard copy portions 
of the monitoring plan shall be kept on record according to section 
10.1 of this appendix.
    11.4 Certification, Recertification, and Quality-Assurance Test 
Reporting Requirements. Use CEDRI to submit the results of all 
required certification, recertification, quality-assurance, and 
diagnostic tests of the monitoring systems required under this 
appendix electronically. Submit the test results concurrent with the 
quarterly electronic emissions report. However, for RATAs of the EtO 
monitor, if this is not possible, you have up to 60 days after the 
test completion date to submit the test results; in this case, you 
may claim provisional status for the emissions data affected by the 
test, starting from the date and hour in which the test was 
completed and continuing until the date and hour in which the test 
results are submitted. If the test is successful, the status of the 
data in that time period changes from provisional to quality-
assured, and no further action is required. However, if the test is 
unsuccessful, the provisional data must be invalidated and 
resubmission of the affected emission report(s) is required.
    11.4.1 For each daily CD (or calibration error) assessment 
(including daily calibration transfer standard tests), and for each 
seven-day calibration drift (CD) test of an EtO monitor, report:
    11.4.1.1 Facility ID information;
    11.4.1.2 The monitoring component ID;
    11.4.1.3 The instrument span and span scale;
    11.4.1.4 For each gas injection, the date and time, the 
calibration gas level (zero or high-level), the reference gas value 
(ppbv), and the monitor response (ppbv);
    11.4.1.5 A flag to indicate whether dynamic spiking was used for 
the high-level value;
    11.4.1.6 Calibration drift (percent of span or reference gas, as 
applicable);
    11.4.1.7 When using the dynamic spiking option, the measured 
concentration of native EtO before and after each mid-level spike 
and the spiked gas dilution factor; and
    11.4.1.8 Reason for test.
    11.4.2 For each RATA of an EtO CEMS, report:
    11.4.2.1 Facility ID information;
    11.4.2.2 Monitoring system ID number;
    11.4.2.3 Type of test (i.e., initial or annual RATA);
    11.4.2.4 Reason for test;
    11.4.2.5 The reference method used;
    11.4.2.6 Starting and ending date and time for each test run;
    11.4.2.7 Units of measure;
    11.4.2.8 The measured reference method and CEMS values for each 
test run, on a consistent moisture basis, in appropriate units of 
measure;
    11.4.2.9 Flags to indicate which test runs were used in the 
calculations;
    11.4.2.10 Arithmetic mean of the CEMS values, of the reference 
method values, and of their differences;
    11.4.2.11 Standard deviation, using equation 7 in section 12.6 
of PS 19 in appendix B to part 60 of this chapter;
    11.4.2.12 Confidence coefficient, using equation 8 in section 
12.6 of PS 19 in appendix B to part 60 of this chapter;
    11.4.2.13 t-value; and
    11.4.2.14 Relative accuracy calculated using equation 11 in 
section 12.6 of PS 19 in appendix B to part 60 of this chapter.
    11.4.3 For each measurement error (ME) test of an EtO monitor, 
report:
    11.4.3.1 Facility ID information;
    11.4.3.2 Monitoring component ID;
    11.4.3.3 Instrument span and span scale;
    11.4.3.4 For each gas injection, the date and time, the 
calibration gas level (zero, low, mid, or high), the reference gas 
value in ppbv and the monitor response.
    11.4.3.5 For extractive CEMS, the mean reference value and mean 
of measured values at each reference gas level (ppbv).
    11.4.3.6 ME at each reference gas level; and
    11.4.3.7 Reason for test.
    11.4.4 For each interference test of an EtO monitoring system, 
report:
    11.4.4.1 Facility ID information;
    11.4.4.2 Date of test;
    11.4.4.3 Monitoring system ID;
    11.4.4.4 Results of the test (pass or fail);
    11.4.4.5 Reason for test; and
    11.4.4.6 A flag to indicate whether the test was performed: On 
this particular monitoring system; on one of multiple systems of the 
same type; or by the manufacturer on a system with components of the 
same make and model(s) as this system.
    11.4.5 For each LOD test of an EtO monitor, report:
    11.4.5.1 Facility ID information;
    11.4.5.2 Date of test;
    11.4.5.3 Reason for test;
    11.4.5.4 Monitoring system ID;
    11.4.5.5 A code to indicate whether the test was done in a 
controlled environment or in the field;
    11.4.5.6 EtO reference gas concentration;
    11.4.5.7 EtO responses with interference gas (seven 
repetitions);
    11.4.5.8 Standard deviation of EtO responses;
    11.4.5.9 Effective spike addition gas concentrations;
    11.4.5.10 EtO concentration measured without spike;
    11.4.5.11 EtO concentration measured with spike;
    11.4.5.12 Dilution factor for spike;
    11.4.5.13 The controlled environment LOD value (ppbv or ppbv-
meters);
    11.4.5.14 The field determined standard addition detection level 
(SADL in ppbv or ppbv-meters); and
    11.4.5.15 Result of LOD/SADL test (pass/fail).
    11.4.6 For each ME or LOD response time test of an EtO monitor, 
report:
    11.4.6.1 Facility ID information;
    11.4.6.2 Date of test;
    11.4.6.3 Monitoring component ID;
    11.4.6.4 The higher of the upscale or downscale tests, in 
minutes; and
    11.4.6.5 Reason for test.
    11.4.7 For each quarterly RAA of an EtO monitor, report:
    11.4.7.1 Facility ID information;
    11.4.7.2 Monitoring system ID;
    11.4.7.3 Begin and end time of each test run;
    11.4.7.4 The reference method used;
    11.4.7.5 The reference method and CEMS values for each test run, 
including the units of measure;
    11.4.7.6 The mean reference method and CEMS values for the three 
test runs;
    11.4.7.7 The calculated relative accuracy, percent; and
    11.4.7.8 Reason for test.
    11.4.8 For each quarterly cylinder gas audit of an EtO monitor, 
report:
    11.4.8.1 Facility ID information;
    11.4.8.2 Monitoring component ID;
    11.4.8.3 Instrument span and span scale;
    11.4.8.4 For each gas injection, the date and time, the 
reference gas level (zero, mid, or high), the reference gas value in 
ppbv, and the monitor response.
    11.4.8.5 For extractive CEMS, the mean reference gas value and 
mean monitor response at each reference gas level (ppbv).
    11.4.8.6 ME at each reference gas level; and
    11.4.8.7 Reason for test.
    11.4.9 For each quarterly DSA of an EtO monitor, report:
    11.4.9.1 Facility ID information;
    11.4.9.2 Monitoring component ID;
    11.4.9.3 Instrument span and span scale;
    11.4.9.4 For the zero gas injection, the date and time, and the 
monitor response (Note: The zero gas injection from a calibration 
drift check performed on the same day as the upscale spikes may be 
used for this purpose.);
    11.4.9.5 Zero spike error;
    11.4.9.6 For the upscale gas spiking, the date and time of each 
spike, the reference gas level (mid- or high-), the reference gas 
value (ppbv), the dilution factor, the native EtO concentrations 
before and after each spike, and the monitor response for each gas 
spike;
    11.4.9.7 Upscale spike error;
    11.4.9.8 DSA at the zero level and at each upscale gas level; 
and
    11.4.9.9 Reason for test.
    11.4.10 Reporting Requirements for Diluent Gas, Flow Rate, and 
Moisture Monitoring Systems. For the certification, recertification, 
diagnostic, and QA tests of stack gas flow rate, moisture, and 
diluent gas monitoring systems that are certified and quality-
assured according to part 75 of this chapter, report the information 
in section 10.1.8.2 of this appendix.
    11.5 Quarterly Reports.
    11.5.1 The owner or operator of any affected unit shall use 
CEDRI to submit electronic quarterly reports to the Administrator in 
an XML format specified by the Administrator, for each affected unit 
(or group of units monitored at a common stack). If the certified 
EtO CEMS is used for the initial compliance demonstration, EtO 
emissions reporting shall begin with the first operating hour of the 
30-operating day compliance demonstration period. Otherwise, EtO 
emissions reporting shall begin with the first operating hour after 
successfully completing all required certification tests of the 
CEMS.
    11.5.2 The electronic reports must be submitted within 30 days 
following the end

[[Page 24203]]

of each calendar quarter, except for units that have been placed in 
long-term cold storage.
    11.5.3 Each electronic quarterly report shall include the 
following information:
    11.5.3.1 The date of report generation;
    11.5.3.2 Facility identification information;
    11.5.3.3 The information in sections 10.1.2 through 10.1.4 of 
this appendix, as applicable to the type(s) of monitoring system(s) 
used to measure the pollutant concentrations and other necessary 
parameters.
    11.5.3.4 The results of all daily calibrations (including 
calibration transfer standard tests) of the EtO monitor as described 
in section 10.1.8.1.1 of this appendix; and
    11.5.3.5 If applicable, the results of all daily flow monitor 
interference checks, in accordance with section 10.1.8.2 of this 
appendix.
    11.5.4 Compliance Certification. Based on reasonable inquiry of 
those persons with primary responsibility for ensuring that all EtO 
emissions from the affected unit(s) have been correctly and fully 
monitored, the owner or operator shall submit a compliance 
certification in support of each electronic quarterly emissions 
monitoring report. The compliance certification shall include a 
statement by a responsible official with that official's name, 
title, and signature, certifying that, to the best of his or her 
knowledge, the report is true, accurate, and complete.

[FR Doc. 2024-05905 Filed 4-4-24; 8:45 am]
BILLING CODE 6560-50-P