contained HFC-32 AC and HP units referenced in SNAP Rule 19 use
conditions, stating that ``The ignition source examples that EPA cites
in the quoted language [e.g., static electricity, a spark resulting
from a closing door, or a cigarette] in the preceding sentence are
incorrect.''
    Response: EPA acknowledges Daikin's comment regarding ignition
sources for

self-contained HFC-32 AC and HP units referenced in the preamble for
the original listing published in SNAP Rule 19. The examples of
ignition sources that Daikin cites were appropriate for certain ASHRAE
34 classified A3 hydrocarbon refrigerants in the context of SNAP Rule
19 listings. Given that HFC-32 is classified as an A2L, Daikin is
correct that static electricity, a spark resulting from a closing door,
or a cigarette are not considered sufficient to be ignition sources for
it. HFC-32 and other A2L refrigerants require a higher amount of energy
to ignite than A3 refrigerants. Examples of ignition sources with
enough energy to ignite an A2L refrigerant, found empirically, are a
hot wire at 800 [deg]C or open flames such as from a butane lighter or
a lit candle coming into contact directly with a refrigerant leak (Kim
and Sunderland, 2018).\39\ This experiment also found that many other
potential ignition sources are insufficient to ignite HFC-32 and
certain other A2L refrigerants, such as cigarettes, electric plug and
receptacle, friction sparks, hair dryers, and space heaters. In
response to Daikin's comment, EPA has changed the language in the
preamble for this final rule from the July 2022 NPRM for HFC-32 in new
self-contained room ACs and HPs in section II.D, above, to reflect more
appropriate ignition sources for HFC-32. We are now clarifying the
characterization of the A2L ignition source that we provided in the
preamble for the original listing in SNAP Rule 19 and the NPRM for this
final rulemaking. That clarification does not affect EPA's view that
the final use conditions for HFC-32 described above are appropriate.
---------------------------------------------------------------------------

    \39\ Dennis Kim and Peter Sunderland, ``Viability of Various
Ignition Sources to Ignite A2L Refrigerant Leaks,'' 17th
International Refrigeration and Air Conditioning Conference at
Purdue University, July, 2018. Available online at: https://docs.lib.purdue.edu/cgi/viewcontent.cgi?article=2885&context=iracc.
---------------------------------------------------------------------------

E. Use Conditions and Further Information in Final Listings for
Chillers, Residential Dehumidifiers, and HFC-32 in Self-Contained Room
ACs and HPs

1. What use conditions is EPA finalizing and why?
    As described above, EPA is listing:

 HFO-1234yf, HFC-32, R-452B, R-454A, R-454B, and R-454C as
acceptable, subject to use conditions, for use in centrifugal and
positive displacement chillers for new equipment in comfort cooling
applications, including commercial AC and IPAC
 HFO-1234yf, HFC-32, R-452B, R-454A, R-454B, and R-454C as
acceptable, subject to use conditions, for use in residential
dehumidifiers for new equipment

    In addition, EPA is finalizing revisions to the use conditions that
apply to the listing of:

     HFC-32 as acceptable, subject to use conditions, for use
in self-contained room ACs and HPs for new equipment

    These use conditions are summarized in the listings under
subheadings II.A and II.B and the revisions to the use conditions are
summarized under subheading II.D, above, and are explained here in
greater detail. The use conditions EPA is finalizing (either as new
listings or revisions to a previous listing) include conditions
requiring use of each refrigerant in new equipment, which can be
specifically designed for the refrigerant; use consistent with the UL
60335-2-40 industry standard, 3rd Edition, including testing, charge
sizes, ventilation, usage space requirements, and certain hazard
warnings and markings; and requirements for warning labels and markings
on equipment to inform consumers and technicians of potential
flammability hazards. The listings with specific use conditions are
intended to allow for the use of these lower flammability refrigerants
in a manner that will ensure they do not pose a greater overall risk to
human health and the environment than other substitutes in these end-
uses.
New Equipment Only; Not Intended for Use as a Retrofit Alternative
    EPA is finalizing that these refrigerants may be used only in new
equipment which has been designed to address concerns unique to
flammable refrigerants--i.e., none of these substitutes may be used as
a conversion or ``retrofit'' refrigerant for existing equipment. The
information that EPA has considered in our review of flammability risks
of this refrigerant in this end-use is based on designing and testing
new equipment and not on mitigation methods specific to retrofitting of
existing equipment designed for non-flammable refrigerants. Neither the
submitters nor public commenters suggested that EPA should consider
listing the refrigerants covered by this rule for chillers,
dehumidifiers, or self-contained room ACs and HPs for retrofit use.
Therefore, EPA is finalizing that they may only be used in new
equipment which can be properly designed for their use. This use
condition does not affect the ability to service a system using the
refrigerant once installed, including the adding of refrigerant or
replacing components.
    This use condition would not affect the ability to service a system
using one of these refrigerants once installed, including the adding of
refrigerant or replacing components.
Standards
    EPA is finalizing that the flammable refrigerants may be used only
in equipment that meets all requirements in UL Standard 60335-2-40, 3rd
Edition.
    Those participating in the UL 60335-2-40 consensus standards
process have tested equipment for flammability risk and evaluated the
relevant scientific studies. Further, UL has developed safety standards
including requirements for construction and system design, for
markings, and for performance tests concerning refrigerant leakage,
ignition of switching components, surface temperature of parts, and
component strength after being scratched. Certain aspects of system
construction and design, including charge size, ventilation, and
installation space, and greater detail on markings, are discussed
further below in this section. The UL 60335-2-40 Standard was developed
in an open and consensus-based approach, with the assistance of experts
in the AC industry as well as experts involved in assessing the safety
of products. While similar standards exist from other bodies such as
the International Electrotechnical Commission (IEC), we are finalizing
to rely on specific UL standards that are most applicable and
recognized by the U.S. market. This approach is the same as that in our
previous rules on flammable refrigerants (e.g., 76 FR 78832; December
20, 2011, 80 FR 19454; April 10, 2015, and 86 FR 24444; May 6, 2021).
    A summary of the requirements of UL 60335-2-40 as they affect the
refrigerants and end-use addressed in this section of our rule follows.
This summary is offered for information only and does not provide a
complete review of the requirements in this standard.
    Among the provisions in UL 60335-2-40 are limits on the amount of
refrigerant allowed in each type of appliance based on several factors
explained in that standard. The requirements in UL 60335-2-40 reduce
the risk to workers and consumers. Annex GG of the standard provides
the charge limits, ventilation requirements and requirements for
secondary circuits. The standard specifies requirements for
installation space of an appliance (i.e., room floor area) and/or
ventilation or other requirements that are determined according to the
refrigerant charge used

in the appliance, the installation location and the type of ventilation
of the location or of the appliance. Within Annex GG, Table GG.1
provides guidance on how to apply the requirements to allow for safe
use of flammable refrigerants. UL 60335-2-40, 3rd Edition contains
provisions for safety mitigation. These mitigation requirements were
developed to ensure the safe use of flammable refrigerants over a range
of appliances. In general, as larger charge sizes are used, more
stringent mitigation requirements are required by the standard. In
certain applications, refrigerant detection systems (as described in
Annex LL, Refrigerant detection systems for A2L refrigerants) and
refrigerant sensors (as described in Annex MM, Refrigerant sensor
location confirmation tests) such as safety alarms are required by the
standard. Where air circulation (i.e., fans) is required in accordance
with Annex GG or Annex 101.DVG, it must be initiated by a separate
refrigerant detection system either as part of the appliance or
installed separately. In a room with no mechanical ventilation, Annex
GG provides requirements for openings to rooms based on several
factors, including the charge size and the room area. The minimum
opening is intended to be sufficient so that natural ventilation would
reduce the risk of using a flammable refrigerant. The standard also
includes specific requirements covering construction, instruction
manuals, allowable charge sizes, mechanical ventilation, safety alarms,
and shut off valves for A2L refrigerants.
    In addition to Annex GG and Table GG.1 mentioned above, UL 60335-2-
40 has a requirement for the maximum charge for an appliance using an
A2L refrigerant. Additional requirements exist for charge sizes
exceeding three times the LFL.
    Table GG.1 of the UL standard indicates that systems with
refrigerant charges exceeding certain amounts are outside the scope of
the standard, stating that ``National standards apply.'' Specifically,
if the refrigeration circuit with the greatest mass of a flammable
refrigerant is more than 260 times the lower flammability limit (in kg/
m\3\), such equipment is outside the scope. For example, HFC-32 has an
LFL of approximately 0.307 kg/m\3\ (0.0192 lb/ft\3\); therefore,
equipment with charge sizes of a single circuit exceeding 79.82 kg
(176.0 lb) would fall outside the scope of the UL Standard. EPA expects
that many chillers could exceed these charge thresholds and therefore
is proposing that an additional safety standard would apply for all
chillers, as discussed in section II.A.4, above. EPA does not expect
this situation to occur for residential dehumidifiers or self-contained
room ACs and HPs because of their smaller charge sizes.
    EPA recognizes that an updated edition of this standard, Edition 4,
was published on December 17, 2022. Nevertheless, EPA is finalizing
this rulemaking to the 3rd Edition of this standard because the 4th
Edition was not available ahead of the issuance of the proposed rule
for the Agency to consider. Therefore, since the 4th Edition was
published several months after the proposed rule and after the close of
the comment period, EPA could not have reviewed the standard for
inclusion in the proposal and there was no opportunity for public
comment on whether to incorporate it into the use conditions for these
listings. EPA intends to review the 4th edition and if appropriate, EPA
will propose to update the use conditions contained in this final rule
in a subsequent rulemaking.
Warning Labels
    EPA is requiring labeling of chillers and residential
dehumidifiers. In addition, EPA is modifying the previously promulgated
use conditions for HFC-32 self-contained room ACs and HPs
(``equipment'') to update the warning label text. EPA is finalizing
that the following labels, or the equivalent, must be provided in
letters no less than 6.4 mm (\1/4\ inch) high and must be permanent
(except for HFC-32 self-contained equipment opting to follow the
current use conditions in compliance with UL 484, 8th Edition up to and
including its sunset date of January 1st, 2024):

i. On the outside of the equipment: ``WARNING--Risk of Fire. Flammable
Refrigerant Used. To Be Repaired Only By Trained Service Personnel. Do
Not Puncture Refrigerant Tubing''
ii. On the outside of the equipment: ``WARNING--Risk of Fire. Dispose
of Properly In Accordance With Federal Or Local Regulations. Flammable
Refrigerant Used''
iii. On the inside of the equipment near the compressor: ``WARNING--
Risk of Fire. Flammable Refrigerant Used. Consult Repair Manual/Owner's
Guide Before Attempting to Service This Product. All Safety Precautions
Must Be Followed''
iv. For any equipment pre-charged at the factory, on the equipment
packaging or on the outside of the equipment: ``WARNING--Risk of Fire
due to Flammable Refrigerant Used. Follow Handling Instructions
Carefully in Compliance with National Regulations''
1. If the equipment is delivered packaged, this label shall be applied
on the packaging
2. If the equipment is not delivered packaged, this label shall be
applied on the outside of the appliance

    EPA expects that all residential dehumidifiers and all self-
contained room ACs and HPs would be packaged, and hence this label
would be placed as stipulated in item 1 above. For self-contained room
ACs and HPs that are opting to continue being manufactured according to
UL 484, 8th Edition, the existing labeling requirements apply until the
standard sunsets on January 1, 2024, and are described in the section
below. EPA expects that chillers could be provided packaged or not, and
this label would be placed as stipulated in item 1 or 2, respectively.

v. On the equipment near the nameplate:
1. At the top of the marking: ``Minimum installation height, X m (W
ft).'' This marking is only required if the similar marking is required
by the 3rd Edition of UL 60335-2-40. The terms ``X'' and ``W'' shall be
replaced by the numeric height as calculated per the UL Standard. Note
that the formatting here is slightly different than the UL Standard;
specifically, the height in Inch-Pound units is placed in parentheses
and the word ``and'' has been replaced by the opening parenthesis.
2. Immediately below v.1. above or at the top of the marking if v.1. is
not required: ``Minimum room area (operating or storage), Y m\2\ (Z
ft\2\).'' The terms ``Y'' and ``Z'' shall be replaced by the numeric
area as calculated per the UL Standard. Note that the formatting here
is slightly different than the UL Standard; specifically, the area in
Inch-Pound units is placed in parentheses and the word ``and'' has been
replaced by the opening parenthesis.
vi. For non-fixed equipment, including residential dehumidifiers and
self-contained room ACs and HPs, on the outside of the product:
``WARNING--Risk of Fire or Explosion--Store in a well-ventilated room
without continuously operating flames or other potential ignition.''
EPA expects that this label would be required on residential
dehumidifiers, non-residential dehumidifiers, and HFC-32 self-contained
room ACs (e.g., including portable ACs, window ACs, PTACs and PTHPs).
vii. For fixed equipment that is ducted, near the nameplate:
``WARNING--Risk of Fire--Auxiliary devices which may be ignition
sources shall not be

installed in the ductwork, other than auxiliary devices listed for use
with the specific appliance. See instructions.''

    The text of the warning labels, above in i. through iv., vi., and
vii., is exactly the same as that required in UL 60335-2-40, while the
text of the label identified in v. is similar to that in the UL
Standard. The major difference between this rule's warning label
requirements and the requirements in Table 101.DVF.1 of UL 60335-2-40
is that the markings for A2L refrigerants, including HFO-1234yf, HFC-32
and the four refrigerant blends, are required to be no less than 3.2 mm
(\1/8\ inch) high in the standard instead of 6.4 mm (\1/4\ inch) as EPA
is finalizing in this action. EPA considers it difficult to see warning
labels with the minimum lettering height requirement for A2L
refrigerants of 3.2 mm (\1/8\ inch) in the UL Standard. Therefore, as
in the requirements in our previous flammable refrigerants rules (e.g.,
76 FR 78832; December 20, 2011 and 80 FR 19454; April 10, 2015 and 86
FR 24444; May 6, 2021), EPA is finalizing that the minimum height for
lettering must be 6.4 mm (\1/4\ inch) as opposed to 3.2 mm (\1/8\
inch), which will make it easier for technicians, consumers, retail
storeowners, first responders, and those disposing the appliance to
view the warning labels.
    For those manufacturers of new self-contained room ACs and HPs
opting to follow the UL 484, 8th Edition standard up to and including
its sunset date of January 1st, 2024, EPA is finalizing that the
following markings, or the equivalent, must be provided in letters no
less than 6.4 mm (\1/4\ inch) high and must be permanent:
    (a) On the outside of the air conditioner: ``DANGER--Risk of Fire
or Explosion. Flammable Refrigerant Used. To Be Repaired Only By
Trained Service Personnel. Do Not Puncture Refrigerant Tubing.''
    (b) On the outside of the air conditioner: ``CAUTION--Risk of Fire
or Explosion. Dispose of Properly In Accordance With Federal Or Local
Regulations. Flammable Refrigerant Used.''
    (c) On the inside of the air conditioner near the compressor:
``CAUTION--Risk of Fire or Explosion. Flammable Refrigerant Used.
Consult Repair Manual/Owner's Guide Before Attempting To Service This
Product. All Safety Precautions Must Be Followed.''
    (d) On the outside of each portable air conditioner: ``WARNING:
Appliance shall be installed, operated and stored in a room with a
floor area larger the ``X'' m\2\ (Y ft\2\).'' The value ``X'' on the
label must be determined using the minimum room size in m\2\ calculated
using Appendix F of UL 484, 8th Edition.
    However, after the sunset of UL 484 on January 1st, 2024, the use
conditions described above, related to the 3rd edition of UL 60335-2-
40, will apply for all self-contained room ACs and HPs under SNAP.
Markings
    Our understanding of the UL Standard is that red markings, similar
to those EPA has applied as use conditions in past actions for
flammable refrigerants (76 FR 78832; December 20, 2011 and 80 FR 19454;
April 10, 2015 and 86 FR 24444; May 6, 2021), are required by the UL
Standard for A2 and A3 refrigerants but not A2L refrigerants. EPA is
finalizing that such markings apply to these A2L refrigerants as well,
to establish a common, familiar and standard means of identifying the
use of a flammable refrigerant.
    These red markings will help technicians immediately identify the
use of a flammable refrigerant, thereby potentially reducing the risk
of using sparking equipment or otherwise having an ignition source
nearby. The AC and refrigeration industry currently uses red-colored
hoses and piping as means for identifying the use of a flammable
refrigerant based on previous SNAP listings. Likewise, distinguishing
coloring has been used elsewhere to indicate an unusual and potentially
dangerous situation, for example in the use of orange-insulated wires
in hybrid electric vehicles. Currently under the SNAP listings, as
applicable, color-coded hoses or pipes must be used for ethane, HFC-32,
R-452B, R-454A, R-454B, R-454C, R-457A, isobutane, propane, and R-441A
in certain types of equipment where these are listed acceptable,
subject to use conditions. All such tubing must be colored red PMS #185
or RAL 3020 to match the red band displayed on the container of
flammable refrigerants AHRI Guideline N, ``2017 Guideline for
Assignment of Refrigerant Container Colors.'' The intent of this
requirement is to provide adequate notice for technicians and others
that a flammable refrigerant is being used within a particular piece of
equipment or appliance. Another goal is to provide adequate
notification of the presence of flammable refrigerants for personnel
disposing of appliances containing flammable refrigerants. As explained
in a previous SNAP rule, one mechanism to distinguish hoses and pipes
is to add a colored plastic sleeve or cap to the service tube. (80 FR
19465; April 10, 2015). Other methods, such as a red-colored tape could
be used. The colored plastic sleeve, cap, or tape would have to be
forcibly removed in order to access the service tube and would have to
be replaced if removed. This would signal to the technician that the
refrigeration circuit that she/he was about to access contained a
flammable refrigerant, even if all warning labels were somehow removed.
This sleeve, cap or tape would be of the same red color (PMS #185 or
RAL 3020) and could also be boldly marked with a graphic to indicate
the refrigerant was flammable. This could be a cost-effective
alternative to painting or dyeing the hose or pipe.
    EPA is finalizing the use of color-coded hoses or piping as a way
for technicians and others to recognize that a flammable refrigerant is
used in the equipment. This would be in addition to the proposed use of
warning labels discussed above. EPA considers having two such warning
methods to be reasonable and consistent with other general industry
practices. This approach is the same as that adopted in our previous
rules on flammable refrigerants (e.g., 76 FR 78832; December 20, 2011
and 80 FR 19454; April 10, 2015 and 86 FR 24444; May 6, 2021).
2. What additional information is EPA including in these final
listings?
    For chillers, residential dehumidifiers, and self-contained room
ACs and HPs, EPA is including additional information, found in the
``Further Information'' column of the regulatory text at the end of
this document, to protect personnel from the risks of using flammable
refrigerants. Similar to our previous listings of flammable
refrigerants, EPA is including information on the OSHA requirements at
29 CFR part 1910, proper ventilation, personal protective equipment,
fire extinguishers, use of spark-proof tools and equipment designed for
flammable refrigerants, and training. Since this additional information
is not part of the regulatory decision under SNAP, these statements are
not binding for use of the substitute under the SNAP program. While the
items listed are not legally binding under the SNAP program, EPA
encourages users of substitutes to apply all statements in the
``Further Information'' column in their use of these substitutes as
best practices for safer use.

3. How is EPA responding to comments on use conditions and further
information for chillers, residential dehumidifiers, and HFC-32 self-
contained room ACs and HPs?
    Comment: Several commenters (AHRI, the Alliance for Responsible
Atmospheric Policy (the Alliance), Anden, AprilAire, AHAM, ATMOsphere,
Carrier Global Corporation, Competition Advocates, Daikin, Diversified
CPC International, the Environmental Investigation Agency (EIA), GE
Appliances/Haier, LG Electronics U.S.A., Chemours, Trane, UL Solutions)
commented in support of incorporating by reference the industry
standards UL 60335-2-40 and ASHRAE 15 into the use conditions for
chillers, residential dehumidifiers, and self-contained room AC and
HPs, but expressed concerns on the Agency's timing of referencing
specific editions of these standards.
    AHRI, Chemours, and UL stated that a new version of UL 60335-2-40,
the 4th edition, may soon be published. Carrier and Daikin recommended
using the 4th edition of UL 60335-2-40 instead of the proposed 3rd
edition of that standard if the 4th edition is published before EPA
issues a final rulemaking. EIA, an environmental group, stated that the
4th Edition of UL 60335-2-40 should be used in the final rule's use
conditions if published before EPA takes final action on this rule.
Trane recommended delaying approval of SNAP Rule 25 as it relates to
chillers, until it can incorporate by reference the 4th Edition of UL
60335-2-40. UL stated that the 4th edition has many improvements over
the 3rd edition, including updates requested by the fire service
community. Anden and AprilAire both suggested EPA allow for use of the
3rd edition ``in addition to'' the 4th edition, rather than ``in lieu
of'' the 4th edition, as EPA proposed. Chemours and Carrier suggested
that EPA update previous rules with older editions of standards (e.g.,
SNAP Rule 23).
    Some commenters, such as Daikin and Chemours, noted that the 2022
version of ASHRAE 15 was likely to be published a few months after the
NPRM and before the final rule would be issued. UL mentioned the
pending publication of ASHRAE 15-2022, in addition to the May of 2022
version of ASHRAE 15.2, a new residential version of the standard.
Chemours and Carrier also stated that once the new versions of the UL
60335-2-40 and ASHRAE 15 standards are published, the use conditions of
the proposed rule should be updated.
    AHRI stated that it will be important to have a pathway to
compliance as each new edition becomes available. LG Electronics and
AHAM stated that NRTLs do not have a required date to comply with the
3rd edition and expressed concern that this will cause issues in
obtaining proper testing for the products. AHAM commented, particularly
with respect to the use of HFC-32 in self-contained room ACs and HPs,
that the Agency must allow for transition periods within the rule so
that manufactured products can comply with relevant safety standards.
The Alliance commented on their support for dealing with codes and
standards issues raised by AHAM and AHRI. They noted this is a critical
issue and has been a critical issue for several years now, but that
integration of the codes and standards will allow transition schedules
for alternatives. Competition Advocates ``encourage[d] EPA to revise
its proposed SNAP Rule 25 use conditions to allow for an extended
implementation time.'' Trane commented that there should be an
expedited process for updating the linked standards to allow for ease
of compliance and ensure the availability of the latest technologies.
    GE Appliances noted support for SNAP Rule 25 and urged EPA to move
quickly in finalizing. AHAM urged the Agency to ``expedite finalizing
this rule,'' referencing regulations in California limiting refrigerant
options in dehumidifiers as of the start of 2023.
    Response: EPA thanks the commenters for their support of including
ASHRAE 15 and UL 60335-2-40 standards in the use conditions for
chillers, residential dehumidifiers, and self-contained ACs and HPs in
SNAP Rule 25. EPA acknowledges the information on further developments
in the UL 60335-2-40 standard and ASHRAE standards processes and
realizes that new editions of both standards have been published since
the issuance of the proposed rule and after the close of the comment
period. After considering all the public comments on this proposal, we
are finalizing the editions of relevant standards required by the use
conditions for chillers, dehumidifiers, and self-contained ACs and HPs
as proposed. EPA is incorporating by reference the 3rd edition of UL
60335-2-40 and the 2019 edition of ASHRAE 15. The 3rd edition of UL
60335-2-40 includes extensive revisions specifically to address
flammability risks of A2L refrigerants and reach industry-wide
consensus. We conclude that the 3rd edition adequately addresses the
use of these A2L refrigerants in the equipment proposed and as
discussed below, if the Agency determines changes are warranted, the
Agency can do so in a future rulemaking.
    EPA is aware of the new 4th edition of UL 60335-2-40 and the ASHRAE
15-2022 standards that have recently been published. However, these
editions were not available in advance of the development of the
proposed rule and thus were not considered. In addition, the public did
not have the opportunity to review and comment on a proposed rule that
reflected those new editions. EPA recognizes that the UL standards are
under continuous maintenance--as are ASHRAE Standards 15 and 15.2--and
hence may change again, even though the mentioned editions are newly
published. Past experience suggests it is difficult to align the
regulatory development process with these standard-setting processes.
EPA concluded that rather than wait for the issuance of a new edition
(which could be replaced with a subsequent edition), it was important
for EPA to act on the SNAP submissions and propose listings based on
the best available information, which included the available editions
of the relevant UL and ASHRAE standards. Furthermore, now that a 4th
edition of the UL Standard and the 2022 version of ASHRAE 15 are
released, EPA will review the relevant changes and may develop a
subsequent rulemaking, allowing for a notice and comment period for the
public to provide their opinions on the updates.
    Some commenters supported moving forward with the rule using the
3rd edition of UL 60335-2-40 consistent with EPA's proposal. EPA
concludes that reliance on the 3rd edition of the UL Standard, the 2019
version of ASHRAE 15, and other use conditions allows applicable
products to be used safely. Given the comments received expressing
desire for quick finalization of the rule, EPA's understanding that the
3rd edition provides many desired improvements on the 2nd edition, and
environmental benefits to providing these ODS alternatives as quickly
as possible, EPA is finalizing to the 3rd edition of UL 60335-2-40.
    Regarding Trane's comment requesting an expedited updating process
for standards, EPA does not have an automatic process or a process with
fewer steps, as each particular iteration of a standard must be
reviewed by the Agency. Additionally, updating the standard involves a
change to regulations, and the Agency typically uses a notice-and-
comment process to change the standard that is incorporated into
regulations. In response to comments from Chemours and Carrier

that EPA should also update previous rules with older editions of
standards, EPA notes that this is outside the scope of this rulemaking.
EPA will continue to consider changes to relevant standards, both for
this rule and for previous rules addressing flammable refrigerants, and
the Agency may consider whether any revisions to the SNAP program
regulations should be proposed at a future date.
    Comment: Several commenters noted concerns regarding the proposed
use conditions (AHRI, the Alliance, Anden, AprilAire, Competition
Advocates, Daikin, Diversified CPC International). Anden commented on
EPA's proposed use condition requiring ``marked service ports, pipes,
hoses, and other devices through which the refrigerant is serviced''
and requested ``EPA to clarify in the final rule that this particular
use condition does not apply to equipment that does not have service
ports.'' Similar to Anden, AprilAire commented on ``marked service
ports'' and requested ``EPA to clarify in the final rule that this
particular use condition does not apply to equipment that does not have
service ports.'' AprilAire noted that their products generally do not
contain service ports.
    Daikin noted that ``EPA inaccurately characterized the operation of
chillers in its general description of warning label use conditions
``vii. For fixed equipment that is ducted, including chillers. . . .''
87 F.R. at 45523 (emphasis added).''
    Diversified CPC International, a producer of specialty gases,
including hydrocarbon refrigerants, commented on the use of hydrocarbon
refrigerants and noted it has ``been limited within the United States
due to refrigerant charge limitations that are much lower than most
regions in the world. For example, the IEC Standard IEC 60335-2-40
allows for 1,000 grams charge size for indoor air conditioning units
and a 5 kg limit for outdoor air conditioning units.'' They stated that
EPA should consider modifying use conditions to allow compliance for
larger A3 charge sizes for various types of equipment that falls under
the scope of UL 60335-2-40, 3rd Edition and UL 60335-2-89, 2nd Edition.
ATMOsphere, a trade group, stated that the next step for revising North
American safety standards will be to form a CANENA Technical
Harmonization Committee (THC) to discuss possibly adopting changes from
the 7th and most recent edition of the IEC into a future edition 5 of
UL 60335-2-40, with larger charge sizes for hydrocarbons.
    Response: The Agency acknowledges support for the proposed listings
covered by the use conditions in this section of the preamble. After
considering all the public comments on the proposal, we are finalizing
these use conditions, with modifications in response to the comments
received. A few commenters requested clarification on use conditions
requiring ``marked service ports, pipes, hoses, and other devices
through which the refrigerant is serviced.'' EPA considers the marked
service port use condition to apply to equipment without service ports,
as servicing or recovery occurs through their pipes, hoses, or other
devices. Technicians will still need information provided by the
service port markings in these circumstances. After considering all the
public comments on this proposal, we are finalizing this use condition
as proposed.
    EPA agrees with comments provided by Daikin indicating that EPA may
have inadvertently mischaracterized the operation of chillers in its
general description of warning label use conditions. In response to
this comment, EPA has edited the warning label description for fixed
equipment to keep the reference to ducted equipment and to remove the
reference to chillers.
    EPA is aware of the larger charge sizes for hydrocarbon
refrigerants allowed in updated versions of UL standards, such as UL
60335-2-89, 2nd Edition and UL 60335-2-40, 3rd Edition. EPA did not
propose to increase the charge sizes of A3 refrigerants, thus this
request is beyond the scope of this rulemaking. Additionally, EPA did
not consider equipment covered by the UL 60335-2-89 standard in this
rulemaking. Any changes to use conditions for listings not included in
the proposal are beyond the scope of this final rule, and if EPA
concludes that proposing changes to the listings is warranted, it would
typically initiate a separate rulemaking process. The Agency is
familiar with the process of forming a CANENA THC to discuss proposals
for adopting the changes in IEC 60335-2-40 Edition 7 into the next
edition of the North American safety standards, including the 5th
edition of UL 60335-2-40. If a 5th edition of UL 60335-2-40 is
released, EPA can consider any relevant changes such as allowing for
larger charge sizes for hydrocarbon refrigerants in a future
rulemaking.

F. Very Low Temperature Refrigeration (VLTR)--Listing of R-1150 as
Acceptable, Subject to Use Conditions and Narrowed use limits, for Use
in New VLTR

    In the NPRM, EPA proposed to list R-1150 as acceptable, subject to
use conditions and narrowed use limits, for use in new VLTR equipment.
No comments were received in regard to this listing. Therefore, EPA is
finalizing the listing of R-1150 in VLTR as proposed.
1. Background on VLTR
    The very low temperature refrigeration (VLTR) end-use includes a
wide range of equipment types. VLTR equipment is intended to maintain
temperatures considerably lower than for refrigeration of food (below -
62 [deg]C or -80 [deg]F). Examples of very low temperature
refrigeration equipment include medical freezers and freeze-dryers,
which generally require extremely reliable refrigeration cycles to
maintain low temperatures and must meet stringent technical standards.
In some cases, VLTR equipment may use a refrigeration system with two
stages, each with its own refrigerant loop. This allows a greater range
of temperatures and may reduce the overall refrigerant charge.
    For this rulemaking, only equipment designed to reach temperatures
lower than -80 [deg]C (-112 [deg]F) is addressed. See sections II.E.6
and II.E.7 below for a discussion of the narrowed use limits describing
the reasoning for this temperature requirement. Examples of equipment
covered by this final rule in the VLTR end-use include:
     Freeze dryers. This equipment typically includes a two-
stage system, with a VLTR stage being addressed by this rule and a
warmer stage, usually classified as IPR, not addressed in this final
rule. The primary application of this equipment is for freeze drying
material in a laboratory setting.
     Cold traps required to operate below -80 [deg]C or -112
[deg]F. This equipment is used during laboratory evaporation to
condense vapors to prevent them from entering and damaging the pump, or
leaking into the environment, ensuring a closed system within the
vacuum pump.

     Very low temperature freezers designed to reach
temperatures below -80 [deg]C or -112 [deg]F.
    This final listing decision for R-1150 addresses these types of
equipment, as well as other types of VLTR equipment not mentioned that
fit within the narrowed use limits described in section II.F.6, under
SNAP. This listing addresses all types of VLTR equipment that meet the
requirements of the UL Standard 61010-2-011, 2nd Edition, and for all
applications of such equipment under EPA's final use conditions and
narrowed use limits. Because UL Standard 61010-2-011 only applies to
laboratory equipment, we understand that only VLTR equipment that is
also laboratory equipment is eligible to use R-1150 under the use
condition.
2. What is EPA's final listing decision for R-1150?
    EPA is listing R-1150 as acceptable, subject to use conditions and
narrowed use limits, for use in VLTR equipment, including freeze-
dryers, cold traps, and very low temperature freezers.
3. What is R-1150 and how does it compare to other refrigerants in the
same end-use?
    R-1150, also known as ethene or ethylene (CAS Reg. No. 75-85-1), is
an unsaturated hydrocarbon. It is a flammable refrigerant with the
ASHRAE safety classification A3. You may find a copy of the applicants'
submissions, with CBI redacted, providing the required health and
environmental information for this substitute in this end-use in Docket
EPA-HQ-OAR-2021-0836 at https://www.regulations.gov under the names
``Supporting Materials for Rule 25 Listing of R-1150 in Refrigeration
and Air Conditioning. SNAP Submission Received December 3, 2018'' and
``Supporting Materials for Rule 25 Listing of R-1150 in Refrigeration
and Air Conditioning. SNAP Submission Received January 21, 2021.'' EPA
performed an assessment to examine the health and environmental risks
of this substitute. This assessment is available in Docket EPA-HQ-OAR-
2021-0836: ``Risk Screen on Substitutes in Very Low Temperature
Refrigeration (New Equipment). Substitute: R-1150.'' \40\
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    \40\ ICF, 2022o. Risk Screen on Substitutes in Very Low
Temperature Refrigeration (New Equipment); Substitute: R-1150.
---------------------------------------------------------------------------

    Environmental information: R-1150 has an ODP of zero and a GWP of
four.
    In addition to ODP and GWP, EPA evaluated potential impacts of R-
1150 and other hydrocarbon refrigerants on local air quality. R-1150 is
considered a VOC and is not excluded from EPA's regulatory definition
of VOC (see 40 CFR 51.100(s)) for the purpose of addressing the
development of SIPs to attain and maintain the NAAQS. As described
below, EPA estimates that potential emissions of R-1150, when used in
the refrigeration and AC sector in the VLTR end-use consistent with
this listing under the SNAP program, would not have a significant
impact on local air quality.41 42
---------------------------------------------------------------------------

    \41\ ICF, 2014. Assessment of the Potential Impact of
Hyddrocarbon Refrigerants on Ground Level Ozone Concentrations.
February 2014.
    \42\ ICF, 2022p. Additional Assessment of the Potential Impact
of Hydrocarbon Refrigerants on Ground Level Ozone Concentrations.
May 2020.
---------------------------------------------------------------------------

    In response to the increased market share of hydrocarbon
refrigerants, particularly in VLTR applications, EPA conducted
additional analysis of various scenarios to consider the potential
impacts on local air quality if hydrocarbon refrigerants were used in
further applications.\43\ In particular, use of R-1150 in very low
temperature freezers, including VLTR equipment with an IPR stage using
propylene, and the use of R-1150 in retail food refrigeration systems
\44\ were investigated for ground-level ozone effects. The analysis
first considers highly conservative modeling scenarios where a specific
hydrocarbon would be used widely across all end-uses in the
refrigeration and AC sector. Scenario 1b** estimates propylene's
emissions using EPA's Vintaging Model (VM) and Community Multi-stage
Air Quality (CMAQ) model,\45\ and Scenario 1b estimates R-1150's
emissions using the same VM and CMAQ versions as in Scenario 1b**.
---------------------------------------------------------------------------

    \43\ Ibid.
    \44\ EPA is aware that such refrigeration equipment exists in
Europe. Thus, EPA evaluated R-1150 in retail food refrigeration--
stand-alone units as well as in VLTR and other hydrocarbon
refrigerants, to consider the greatest impact that reasonably could
occur when using increasing amounts of such refrigerants.
    \45\ VM IO file_v5.1_10.01.19 and CMAQ 5.2.1 with carbon bond 06
(CB06) mechanism, as cited in ICF, 2022p. Additional Assessment of
the Potential Impact of Hydrocarbon Refrigerants on Ground Level
Ozone Concentrations. May 2020.
---------------------------------------------------------------------------

    Additionally, the analysis also considers the more realistic
scenarios (Scenario 2, Scenario 3a, and Scenario 3b) where hydrocarbons
are modeled only in the end-uses where the SNAP program has already
listed them as acceptable, or for which SNAP submissions or
international market trends indicate HCs soon could be used. Scenario 2
examines the likely emissions of lower maximum incremental reactivity
(MIR) hydrocarbons, propane, isobutane, and ethane, in the residential
and light commercial AC, residential dehumidifiers, retail
refrigeration, and household refrigeration end-uses. Scenarios 3a and
3b also consider the use of higher MIR refrigerants propylene and R-
1150 in laboratory equipment (IPR and VLTR end-uses, respectively) and
R-1150 in small retail food refrigeration equipment (e.g., stand-alone
units) in addition to the hydrocarbon refrigerants used in Scenario 2.
Scenarios 3a and 3b differentiate based on whether propylene and R-1150
would be subject to the venting prohibition under CAA section
608(c)(2). For further information on the specific assumptions, see the
docket for this rulemaking.\46\
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    \46\ ICF, 2014. Op. cit.
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    In highly conservative Scenario 1b, examining widespread R-1150
adoption across the entire refrigeration and AC sector, modeling
predicts that the single 8-hour average ground-level ozone
concentration could increase by 11.7 percent in Los Angeles, which is
the area with the highest level of ground-level ozone pollution in the
United States. However, the assumptions modeled in 1b are highly
unrealistic, given the significantly smaller number of applications in
which R-1150 has been requested for use or is currently being used
globally. VLTR, the only end-use being addressed in this listing,
represents a very small segment of the refrigeration and AC sector.
    In the more realistic scenarios 3a and 3b, where use of propylene
and R-1150 in laboratory equipment and R-1150 in small retail food
refrigeration equipment are included, the 8-hour ground-level ozone
concentration in Los Angeles was found to increase by a maximum of
0.017 percent relative to the NAAQS on the worst modeled day. For
purposes of this SNAP determination, this is not a significant increase
in ground-level ozone. The modeling is also conservative by assuming a
one-for-one substitution of hydrocarbons for current refrigerants
because an actual transition would likely introduce less than one
kilogram of hydrocarbon for each kilogram replaced. As a result of this
analysis, EPA determined that the use of R-1150 consistent with the use
conditions and narrowed use limits finalized in this rulemaking will
not result in significantly greater risk to people's health or the
environment than other alternatives available for the same use.
    Ecosystem effects from R-1150 are expected to be small, as compared
to the effects of other acceptable substitutes in

this end-use. R-1150 is highly volatile and typically evaporates or
partitions to air, rather than contaminating ground or surface waters,
and thus R-1150's effects on aquatic life are expected to be small.
Based on these considerations, R-1150 is not expected to pose a greater
risk of ecosystem effects than other alternatives for these uses.
    Flammability information: ASHRAE Standard 34 classifies R-1150 as a
Class A3 refrigerant.\47\ R-1150 is flammable when its concentration in
the air is in the range of 2.7 percent to 36 percent by volume (27,000
ppm to 360,000 ppm).48 49
---------------------------------------------------------------------------

    \47\ ASHRAE, 2019a. Op. cit.
    \48\ Ibid.
    \49\ ICF, 2022o. Op. cit.
---------------------------------------------------------------------------

    Toxicity and exposure data: Exposure to R-1150 may be hazardous if
inhalation, skin contact, or eye contact with the proposed substitute
occurs at sufficiently high levels. The most likely pathway of exposure
is through inhalation, which can cause symptoms of asphyxiation.
Exposures of R-1150 to the skin may cause frostbite. Exposures of R-
1150 to the eyes could cause eye irritation. These potential health
effects are common to many refrigerants.
    The American Conference of Governmental Industrial Hygienists
(ACGIH) has established a TLV of 200 ppm as an 8-hour TWA for R-1150.
EPA anticipates that users will be able to meet the TLV and address
potential health risks by following the use condition limiting charge
sizes to 150 g and the requirements and recommendations in the
manufacturer's SDS, ASHRAE Standard 15, UL Standard 61010-2-011, 2nd
Edition, and other safety precautions common to the refrigeration and
AC industry.50 51
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    \50\ ASHRAE, 2019b.
    \51\ ICF, 2022o. Op. cit.
---------------------------------------------------------------------------

    Comparison to other substitutes in this end-use: R-1150 has an ODP
of zero, comparable to or less than other listed substitutes in this
end-use with ODPs ranging from zero to 0.098. For new VLTR equipment,
R-1150's GWP of four is comparable to that of other acceptable
substitutes such as ethane and CO2, with respective GWPs of
5.5 and one, and lower than other acceptable substitutes such as R-
410A, R-507A, and HFC-23 with respective GWPs of 1,890, 3,990, and
14,800.
    R-1150 is a VOC that is more photochemically reactive and more
likely to cause ground-level ozone pollution than acceptable
refrigerants in this end-use. For example, R-1150 has a MIR of 9.07 g-
O3/g-substance, which is higher than propane's MIR of 0.56
g-O3/g-substance or ethane's MIR of 0.28 g-O3/g-
substance.\52\ EPA addresses this potential risk through a narrowed use
limit, restricting use of this refrigerant to VLTR equipment designed
to reach temperatures lower than -80 [deg]C (-112 [deg]F). See section
II.F.6 below for a discussion of the finalized narrowed use limits.
---------------------------------------------------------------------------

    \52\ In addition to being an acceptable refrigerant in very low
temperature refrigeration, ethane's MIR is one threshold that EPA
considers in deciding whether a compound makes a negligible
contribution to tropospheric ozone formation and should be excluded
from EPA's regulatory definition of VOC (see 40 CFR 51.100(s)) for
the purpose of addressing the development of SIPs to attain and
maintain the NAAQS.
---------------------------------------------------------------------------

    Flammability risks of R-1150 are comparable to flammability risks
of other available substitutes in the same end-use, such as ethane,
while R-1150's flammability risks are higher than those of nonflammable
refrigerants such as R-410A, CO2, or HFC-23. Flammability
risks can be addressed by following the finalized use conditions, such
as use only in new equipment that is designed and tested to meet the UL
Standard 61010-2-011. See section II.F.4 below for a discussion of the
use conditions.
    Toxicity risks are comparable to or lower than toxicity risks of
other available substitutes in the same end-use. Toxicity risks can be
minimized by use consistent with the TLV issued by the ACGIH, ASHRAE
Standard 15, UL 61010-2-011--which applies under the final use
conditions--and other industry standards, recommendations in the
manufacturer's SDS, and other safety precautions common in the
refrigeration and AC industry.
    Although R-1150 presents a higher risk to local air quality than
other available alternatives for this end-use, other alternatives such
as ethane, propane, and most HFOs or HFCs, that are less
photochemically reactive than R-1150 are not able to attain
temperatures as low as those attainable by R-1150 because of their
higher boiling points. Thus, EPA is finalizing listing this substitute
as acceptable subject to use conditions and narrowed use limits in
VLTR.
4. What use conditions is EPA finalizing?
    (1) EPA is finalizing the following use conditions to address
flammability risks of R-1150: New equipment only--R-1150 may be used
only in new equipment designed specifically and clearly identified for
the refrigerant, i.e., the substitute shall not be used as a conversion
or ``retrofit'' refrigerant for existing equipment.
    (2) UL Standard--R-1150 may be used only in laboratory equipment
that meet all requirements listed in the 2nd edition, dated May 13th,
2021, of UL Standard 61010-2-011, ``Safety Requirements for Electrical
Equipment for Measurement, Control, and Laboratory Use--Part 011:
Particular Requirements for Refrigerating Equipment.'' In cases where
this final rule includes requirements different than those of UL 61010-
2-011, 2nd Edition, EPA is requiring that the equipment meet the
requirements of this final rule in place of the requirements in the UL
Standard. Requirements of note include:
     Warning labels--The following markings, or the equivalent,
must be provided in letters no less than 6.4 millimeter (\1/4\ inch)
high and must be permanent:
    i. Attach near the machine compartment: ``DANGER--Risk of Fire or
Explosion. Flammable Refrigerant Used. To Be Repaired Only By Trained
Service Personnel. Do Not Puncture Refrigerant Tubing''
    ii. Attach near the machine compartment: ``CAUTION--Risk of Fire or
Explosion. Flammable Refrigerant Used. Consult Repair Manual/Owner's
Guide Before Attempting To Service This Product. All Safety Precautions
Must Be Followed.''
    iii. Attach on the exterior of the refrigeration equipment:
``CAUTION--Risk of Fire or Explosion. Dispose of Properly In Accordance
With Federal Or Local Regulations. Flammable Refrigerant Used.''
    iv. Attach near all exposed refrigerant tubing: ``CAUTION--Risk of
Fire or Explosion Due To Puncture Of Refrigerant Tubing; Follow
Handling Instructions Carefully. Flammable Refrigerant Used.''
    v. Attach on the exterior of the refrigeration equipment: ``This
equipment is intended for use in commercial, industrial, or
institutional occupancies as defined in the Safety Standard for
Refrigeration Systems, ANSI/ASHRAE 15.''
    vi. Attach on the exterior of the shipping carton: ``CAUTION--Risk
of Fire or Explosion. Dispose of Properly In Accordance With Federal Or
Local Regulations.''
    vii. The instructions shall include the following warnings as
necessary:
    a. ``WARNING: Ensure all ventilation openings are not obstructed.''
    b. ``WARNING: Do not use mechanical devices or other means to
accelerate the defrosting process, other than those recommended by the
manufacturer.''
    c. ``WARNING: Do not damage the refrigerant circuit.''

     Markings--Equipment must have distinguishing red (PMS #185
or RAL 3020) color-coded hoses and piping to indicate use of a
flammable refrigerant. The laboratory equipment shall have marked
service ports, pipes, hoses and other devices through which the
refrigerant is serviced. Markings shall extend at least 1 inch (25 mm)
from the servicing port and shall be replaced if removed.
    (3) Charge size--Equipment must use no more than 150 g of R-1150 in
each refrigerant circuit using this refrigerant.
    EPA notes that there may be other legal obligations pertaining to
the manufacture, use, handling, and disposal of the proposed
refrigerant that are not included in the information listed in the
tables included in the regulatory text (e.g., the CAA section 608(c)(2)
venting prohibition,\4\ or Department of Transportation requirements
for transport of flammable gases). Flammable refrigerants being
recovered or otherwise disposed of from VLTR appliances are likely to
be hazardous waste under RCRA (see 40 CFR parts 260-270).
5. Why is EPA finalizing these specific use conditions?
    EPA is finalizing listing R-1150 as acceptable, subject to use
conditions, for use in the VLTR end-use for new equipment reaching
temperatures lower than -80 [deg]C (-112 [deg]F). The use conditions
are identified in the listing under subheading II.F.4, above, and are
explained here in greater detail. The use conditions EPA is finalizing
include conditions requiring use of R-1150 in new equipment, which can
be specifically designed for the refrigerant; use consistent with UL
61010-2-011, 2nd Edition, including testing, charge sizes, ventilation,
usage space requirements, and certain hazard warnings and markings; and
limiting charge size to 150 g of R-1150 per refrigerant circuit. The
finalization of these use conditions is intended to allow for the use
of R-1150, a flammable refrigerant, in a manner that will ensure it
does not pose a greater overall risk to human health and the
environment than other substitutes in this end-use.
New Equipment Only; Not Intended for Use as a Retrofit Alternative
    EPA is finalizing that R-1150 may be used only in new equipment
\53\ which has been designed to address concerns unique to flammable
refrigerants--i.e., this substitute may not be used as a conversion or
``retrofit'' refrigerant for existing equipment. The information that
EPA has considered in our review of flammability risks of this
refrigerant in this end-use is based on designing and testing new
equipment, and not on mitigation methods specific to retrofitting of
existing equipment designed for non-flammable refrigerants. Neither the
submitters nor public commenters suggests that EPA should consider
listing R-1150 for retrofit use. Therefore, EPA is finalizing that R-
1150 can only be used in new equipment properly designed for its use.
This requirement does not affect the ability to service equipment using
R-1150 once installed, including the adding of refrigerant or replacing
components.
---------------------------------------------------------------------------

    \53\ This is intended to mean a completely new refrigeration
circuit containing a new compressor, evaporator, and condenser.
---------------------------------------------------------------------------

Standards
    EPA is finalizing that R-1150 may be used only in equipment that
meets all requirements in UL 61010-2-011, 2nd Edition. This UL standard
indicates that refrigerant charges greater than 150 g are beyond its
scope and that additional requirements apply, such as for instance
ASHRAE 15-2019. EPA has only evaluated equipment that fits within the
scope of UL 61010-2-011.
    UL has developed safety standards including requirements for
construction and system design, for markings, and for performance tests
concerning refrigerant leakage, ignition of switching components,
surface temperature of parts, and component strength after being
scratched. Certain aspects of system construction and design, including
charge size, ventilation, and installation space, and greater detail on
markings, are discussed further below in this section. The UL Standard
was developed in an open and consensus-based approach, with the
assistance of experts in the laboratory equipment industry as well as
experts involved in assessing the safety of products. While similar
standards exist from other bodies such as the IEC, we are finalizing to
rely on a specific UL standard that is most applicable and recognized
by the U.S. market. This approach is the same as that in our previous
rules on flammable refrigerants (e.g., 76 FR 78832, December 20, 2011;
80 FR 19454, April 10, 2015; 86 FR 24444, May 6, 2021).
    A summary of the requirements of UL 61010-2-011, 2nd Edition as
they affect R-1150 and the end-use addressed in this section of the
rule follows. This summary is offered for information only and does not
provide a complete review of the requirements in this standard. UL
61010-2-011, 2nd Edition requires the warning labels on the equipment
to contain letters at least \1/4\ inch high. The label must be
permanently affixed to the equipment. Warning label language
requirements are described in section II.F.4 of this proposed rule.
Additionally, red markings, similar to those EPA has applied as use
conditions in past actions for flammable refrigerants (76 FR 78832,
December 20, 2011; 80 FR 19454, April 10, 2015; 86 FR 24444, May 6,
2021), are required by UL 61010-2-011, 2nd Edition for A2 and A3
refrigerants to establish a common, familiar and standard means of
identifying the use of a flammable refrigerant.
    These red markings will help technicians immediately identify the
use of a flammable refrigerant, thereby potentially reducing the risk
of using sparking equipment or otherwise having an ignition source
nearby. The colored plastic sleeve or cap would have to be forcibly
removed in order to access the service port, hose, or pipe. This would
signal to the technician that the refrigeration circuit that she/he was
about to access contained a flammable refrigerant, even if all warning
labels were somehow removed. This sleeve would be of the same red color
(PMS #185 or RAL 3020) and could also be boldly marked with a graphic
to indicate the refrigerant was flammable. The use of a colored plastic
sleeve or cap that is boldly marked with a graphic could be a cost-
effective alternative to painting or dyeing the service port, hose, or
pipe.
Charge Size Limitation
    Among the provisions in UL 61010-2-011, 2nd Edition are limits on
the amount of refrigerant allowed in each appliance. The limitations on
refrigerant charge size for VLTR are consistent with UL 61010-2-011,
2nd Edition to reduce the risk to workers and consumers. EPA is
requiring a charge size limit of 150 g for each refrigerant circuit or
stage for the proposed refrigerant. Section 1.1.1 of the UL Standard
states, ``This document details all the requirements when up to 150 g
of FLAMMABLE REFRIGERANT are used per stage of a REFRIGERATING SYSTEM.
Additional requirements beyond the current scope of this document apply
if a REFRIGERANT charge of FLAMMABLE REFRIGERANT exceeds this amount.''
Thus, in order to ensure the standard's provisions apply and
sufficiently address flammability risk, EPA is requiring that each
refrigerant circuit must contain no more than 150 g of R-1150.
    In addition to the general requirement that each refrigerant
circuit must contain no more than 150 g of R-1150,

UL 61010-2-011, 2nd Edition has a requirement for the maximum charge
for remote condensing unit using a flammable refrigerant in Annex DD
and Table DD.1. Section DD.2.4 of Annex DD sets requirements for the
minimum associated room area for a given charge, based on a maximum
refrigerant concentration of 0.38 lb/1000 ft\3\, 5200 ppm, or 6 g/m\3\
for R-1150.
6. What narrowed use limits is EPA finalizing?
    EPA is finalizing the following narrowed use limits for use of R-
1150 in VLTR:
    (1) Temperature range--R-1150 may only be used in equipment
designed specifically to reach temperatures lower than -80 [deg]C (-112
[deg]F).
    (2) The manufacturers of new very low temperature equipment must
demonstrate that other alternatives are not technically feasible. They
must document the results of their evaluation that showed the other
alternatives to be not technically feasible and maintain that
documentation in their files. This documentation, which does not need
to be submitted to EPA unless requested to demonstrate compliance,
``shall include descriptions of substitutes examined and rejected,
processes or products in which the substitute is needed, reason for
rejection of other alternatives, e.g., performance, technical or safety
standards, and the anticipated date other substitutes will be available
and projected time for switching to other available substitutes.'' (40
CFR 82.180(b)(3)).
7. Why is EPA finalizing these specific narrowed use limits?
    The boiling point (b.p.) of a refrigerant determines the coldest
temperature it can reach within its refrigerating capabilities. R-1150
has a b.p. of -104 [deg]C, allowing it to refrigerate as cold as -104
[deg]C. There are a limited number of refrigerants that are capable of
reaching temperatures below -80 [deg]C, such as the ODSs CFC-13 (b.p.,
-81.4 [deg]C) and R-503 (b.p., -88.9 [deg]C), and among the acceptable
refrigerants in this end-use, ethane (b.p., -88.3 [deg]C) and the high
GWP refrigerants HFC-23 (b.p., -84.4 [deg]C), R-508A (b.p., -87.4
[deg]C) and R-508B (b.p., -87.4 [deg]C).\54\ Given the limited
refrigerant options available for equipment designed to reach the sub -
80 [deg]C temperature range, EPA understands there is a need for
listing R-1150. However, EPA believes that limiting the use of R-1150
to VLTR equipment designed to reach temperatures lower than -80 [deg]C
(-112 [deg]F) is necessary to mitigate local air quality concerns
discussed in section II.F.3 that could occur with broad use, given the
reactivity of VOC and its potential to contribute to ground-level ozone
in areas like Los Angeles. If R-1150 were used without limitation
across the refrigeration and AC sector, it could have significant
impacts on local air quality. For equipment in this end-use designed to
reach temperatures higher than -80 [deg]C (-112 [deg]F), other
alternatives with lower reactivities are widely available, e.g.,
CO2, ethane, propane, and R-410A. There are sufficient
refrigerant options available to fill the need in VLTR equipment
designed to reach temperatures higher than -80 [deg]C (-112 [deg]F)
without allowing the use of refrigerants as photochemically reactive as
R-1150. By including narrowed use limits, EPA is only allowing the use
of R-1150, a refrigerant with higher reactivity, when it is the only
technically feasible option available.
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    \54\ Engineering ToolBox, 2005. Refrigerants--Physical
Properties. Available online at: https://www.engineeringtoolbox.com/refrigerants-d_902.html Accessed October 28, 2021.
---------------------------------------------------------------------------

8. What additional information is EPA including in this final listing?
    EPA is providing additional information related to this listing.
Since this additional information is not part of the regulatory
decision under SNAP, these statements are not binding for use of the
substitute under the SNAP program. See section II.E.2 above for further
discussion on what additional information EPA is including in this
final listing. While the items listed are not legally binding under the
SNAP program, EPA encourages users of substitutes to apply all
statements in the ``Further Information'' column in their use of these
substitutes as best practices for safer use.
9. How is EPA responding to comments on VLTR?
    No comments were received relating to the proposed listing of R-
1150 in VLTR. For the reasons explained above, EPA is finalizing this
section of the rule as proposed.

G. Streaming and Total Flooding Fire Suppression--Listing of 2-bromo-
3,3,3 trifluoropropene (2-BTP) as Acceptable, Subject to Use
Conditions, as a Streaming Agent in Non-Residential Applications and as
a Total Flooding Agent in Normally Unoccupied Spaces Under 500 ft\3\

1. Background on Streaming and Total Flooding Fire Suppression
    The fire suppression and explosion protection end-uses addressed in
this action are total flooding and streaming. Total flooding systems,
which historically employed halon 1301 as a fire suppression agent, are
used in both normally occupied and unoccupied areas. In the United
States, approximately 90 percent of installed total flooding systems
protect anticipated hazards from ordinary combustibles (i.e., Class A
fires), while the remaining ten percent protect against applications
involving flammable liquids and gases (i.e., Class B fires).\55\ It is
also estimated that approximately 75 percent of total flooding systems
protect electronics (e.g., computers, telecommunications, process
control areas), while the remaining 25 percent protect other
applications, primarily in civil aviation (e.g., engine nacelles/
auxiliary power units, cargo compartments, lavatory trash receptacles),
military weapons systems (e.g., combat vehicles, machinery spaces on
ships, aircraft engines and tanks), oil/gas and manufacturing
industries (e.g., gas/oil pumping, compressor stations), and maritime
(e.g., machinery space, cargo pump rooms). Streaming applications,
which have historically used halon 1211 as an extinguishing agent,
include portable fire extinguishers designed to protect against
specific hazards.
---------------------------------------------------------------------------

    \55\ Wickham, 2002. Status of Industry Efforts to Replace Halon
Fire Extinguishing Agents. March 2002.
---------------------------------------------------------------------------

2. What is EPA's final listing decision for 2-BTP?
    As proposed, EPA is finalizing listing 2-BTP as acceptable, subject
to use conditions. The use conditions are for use in normally
unoccupied spaces under 500 ft\3\ in total flooding fire suppression
systems, and as a streaming agent for use in non-residential
applications, except for commercial home office and personal
watercraft. EPA received one comment on the proposed listing of 2-BTP,
and the commenter supported finalizing the rule as proposed. 2-BTP was
previously listed as acceptable, subject to use conditions, for use in
engine nacelles and auxiliary power units on aircraft in total flooding
fire suppression systems and for use in aircraft as a streaming agent
(81 FR 86778, December 1, 2016).
    The redacted submission and supporting documentation for 2-BTP are
provided in the docket for this proposed rule (EPA-HQ-OAR-2021-0836) at
https://www.regulations.gov. EPA performed assessments to examine the
health and environmental risks of this substitute during equipment
production operations and the filling of

fire extinguishers as well as in the case of an inadvertent discharge
of the system during maintenance activities on the fire extinguishing
system. These assessments are available in the docket for this
rule.56 57
---------------------------------------------------------------------------

    \56\ ICF, 2022q. Risk Screen on Substitutes in Total Flooding
Systems in Normally Unoccupied Spaces. Substitute: 2-bromo-3,3,3-
trifluoropropene (2-BTP).
    \57\ ICF, 2022r. Risk Screen on Substitutes as Streaming Agents
in Non-Residential Applications. Substitute: 2-bromo-3,3,3-
trifluoropropene (2-BTP).
---------------------------------------------------------------------------

3. What is 2-BTP and how does it compare to other fire suppressants in
the same end-uses?
a. Total Flooding
    Environmental information: 2-BTP has an ODP of 0.0028
58 59 60 and a GWP of 0.23-0.26.\61\ 2-BTP is considered a
VOC and is not excluded from EPA's regulatory definition of VOC (see 40
CFR 51.100(s)) for the purpose of addressing the development of SIPs to
attain and maintain the NAAQS.
---------------------------------------------------------------------------

    \58\ Patten, et al., 2011. OH, reaction rate constant, IR
absorption spectrum, ozone depletion potentials and global warming
potentials of 2-bromo-3,3,3-trifluoropropene, J. Geophys. Res., 116
(D24), D24307, doi: 10.1029/2011JD016518, 2011.
    \59\ Orkin, V. L. 2004. Photochemical Properties of 2-bromo-
3,3,3-trifluoropropene and semi-empirical kinetic estimates of its
Global Impacts on the Atmosphere. Prepared by the National Institute
of Standards and Technology Physical and Chemical Properties
Division for American Pacific Corporation. July 2004.
    \60\ The ODP in this rulemaking remains as it was originally
listed by SNAP (see 81 FR 86778).
    \61\ Patten et al., 2012. Correction to ``OH reaction rate
constant, IR absorption spectrum, ozone depletion potentials and
global warming potentials of 2-bromo-3,3,3-trifluoropropene,'' J.
Geophys. Res., 117, D22301, doi:10.1029/2012JD019051.
---------------------------------------------------------------------------

    Flammability information: 2-BTP is non-flammable.
    Toxicity and exposure data: EPA assessed potential health risks
from exposure to the proposed substitute as a total flooding agent in
normally unoccupied spaces up to 14.2 m\3\ (500 ft\3\) during
manufacture, installation, and servicing of 2-BTP total flooding
systems, consistent with the use description provided by the submitter.
According to the SDS, exposure to 2-BTP following a discharge may be
hazardous if inhalation, skin contact, or eye contact with the proposed
substitute occurs at sufficiently high levels. However, the most likely
pathway of exposure is through inhalation, which may cause central
nervous system effects, such as dizziness, confusion, physical
incoordination, drowsiness, anesthesia, or unconsciousness. The
cardiotoxic Lowest Observed Adverse Effect Level (LOAEL) for this agent
is 1.0 percent (10,000 ppm), at which level exposure may cause
increased sensitivity of the heart to adrenaline, which might cause
irregular heartbeats and possibly ventricular fibrillation or death.
    2-BTP vapors may reduce oxygen available for breathing, causing
asphyxiation in high concentrations. Such vapors pose a potential
hazard if large volumes are trapped in enclosed or low places. In
addition, as noted above, if person(s) are exposed to high
concentrations, the person(s) may experience central nervous system
effects, such as drowsiness and dizziness, which may result in the
person(s) not realizing that he/she is suffocating. These health
effects after exposure are similar for other common fire suppressants.
    To assess potential health risks from exposure to the proposed
substitute for personnel during manufacturing, EPA developed an AEL of
2 ppm for 2-BTP based on review of available toxicity studies.\62\ The
AEL represents the maximum 8-hour TWA at which personnel in an
occupational environment can be exposed regularly without adverse
effects. The estimated exposure values provided by the submitter are
greater than the occupational AEL. To effectively mitigate potential
occupational exposure and maintain average exposure levels below the
occupational AEL of 2 ppm, the manufacturing space should be equipped
with specialized engineering controls and well ventilated with a local
exhaust system and low-lying source ventilation. The sampling data
provided by the submitter demonstrate that local exhaust ventilation
greatly reduces exposure concentration inside the fill booth and in the
filling area.
---------------------------------------------------------------------------

    \62\ ICF, 2022r. Risk Screen on Substitutes in Total Flooding
Systems in Normally Unoccupied Spaces. Substitute: 2-bromo-3,3,3-
trifluoropropene (2-BTP).
---------------------------------------------------------------------------

    Exposure to the substitute is not likely during installation or
servicing of 2-BTP total flooding systems for normally unoccupied
spaces. The risk of accidental activation of the fire extinguishing
system while personnel are present near the protected space is highly
unlikely if proper procedures are followed. Proper instructions on
system installation and servicing included in manuals for the 2-BTP
systems should be adhered to. In the case of accidental release,
engineering controls in accordance with the National Fire Protection
Association (NFPA) 2001 Standard on Clean Agent Fire Extinguishing
Systems to limit personnel exposure to discharges should be employed
with 2-BTP systems.
    EPA provides additional information on safe use of this substitute
for establishments manufacturing, installing and maintaining equipment
using this agent in the ``Further Information'' column of the
regulatory listing. EPA recommends that a discharge time delay of 30 to
60 seconds is programmed in accordance with the NFPA 2001 standard.
Although exposure is highly unlikely during installation and
maintenance activities, exposure is possible upon reentry into a space
after a system has been discharged. In the event of an accidental
release, the space should be adequately ventilated. EPA recommends that
personnel wear protective clothing, goggles, gloves, and particulate-
removing respirators with National Institute for Occupational Safety
and Health (NIOSH) type N95 or better filters while performing
installation or maintenance, and a self-contained breathing apparatus
(SCBA) while performing clean-up activities to reduce the risk of
exposure. Since this additional information is not part of the
regulatory decision under SNAP, these statements are not binding for
use of the substitute under the SNAP program. While the items listed
are not legally binding under the SNAP program, EPA encourages users of
substitutes to apply all statements in the ``Further Information''
column in their use of this substitute as best practices for safer use.
    2-BTP is not expected to cause a significant risk to human health
in the general population when used in total flooding systems in
normally unoccupied areas. The use in spaces under 500 ft\3\ requires a
smaller amount of fire suppressant, reducing potential exposures to
workers and the general public and reducing potential toxicity risks.
Disposal of 2-BTP total flooding systems is subject to local, State,
and Federal regulations, which ensure that 2-BTP and water contaminated
with 2-BTP are not to be dumped into sewers, on the ground, or into any
body of water, but rather taken to a wastewater treatment facility or
disposed of properly. 2-BTP is not considered to be hazardous waste
under EPA regulations implementing RCRA at 40 CFR part 261.
    Comparison to other fire suppressants: 2-BTP has an ODP of 0.0028,
comparable to or lower than other acceptable substitutes in this end-
use, with ODPs ranging from zero to 0.048. 2-BTP has a GWP of 0.23-0.26
that is lower than or comparable to that of other acceptable
substitutes for total flooding agents, with GWPs that range from about
zero to 22,800.\63\ 2-BTP is

considered a VOC and is not excluded from EPA's regulatory definition
of VOC (see 40 CFR 51.100(s)) for the purpose of addressing the
development of SIPs to attain and maintain the NAAQS. Other acceptable
fire suppression agents currently in use in this end-use are also VOC
(e.g., C6-perfluoroketone), and 2-BTP is anticipated to pose
no greater risk than other alternatives listed as acceptable in this
end-use. Emissions of 2-BTP should be controlled by adhering to
standard industry practices. Toxicity risks can be minimized by use
consistent with the NFPA 2001 standard, recommendations in the SDS, and
other safety precautions common in the fire suppression industry. The
potential toxicity risks due to inhalation exposure are common to many
total flooding agents, including those already listed as acceptable
under SNAP for this same end-use. 2-BTP post-activation products are
nonflammable, as are all other available total flooding agents.
---------------------------------------------------------------------------

    \63\ For SF6, the substitute with the highest GWP,
the SNAP listing finds SF6 as ``acceptable subject to
narrowed use limits.''
---------------------------------------------------------------------------

    EPA is finalizing listing 2-BTP as acceptable, subject to use
conditions, as a total flooding agent for use in normally unoccupied
spaces under 500 ft\3\ because the overall environmental and human
health risk posed by the substitute is lower than or comparable to the
overall risk posed by other alternatives listed as acceptable in the
same end-use.
b. Streaming Uses
    Environmental information: The environmental information for this
substitute is set forth in the ``Environmental information'' section in
listing II.G.3.a above.
    Flammability information: 2-BTP is non-flammable.
    Toxicity and exposure data: Toxicity and personal protective
equipment (PPE) information is described above under total flooding
applications. EPA evaluated occupational and general population
exposure at manufacture and at end-use to ensure that the use of 2-BTP
as a streaming agent will not pose unacceptable risks to workers or the
general public. For the occupational exposure assessment, EPA has
evaluated the risks associated with potential exposures to 2-BTP during
equipment production operations and the filling of fire extinguishers
as well as in the case of an inadvertent discharge of the fire
extinguisher during maintenance activities.
    2-BTP is not expected to pose a risk to workers during manufacture
of 2-BTP fire extinguishers when the engineering controls and PPE
requirements as referenced in the SDS for this substitute are followed.
The potential health risks from exposure to the substitute for
personnel during manufacturing is described above under total flooding
applications.
    EPA also assessed potential end-use exposure scenarios at 7.5-
minute and 15-minute TWA exposures for 2-BTP following potential
release of agent from the handheld extinguisher in confined spaces
(e.g., electronics and server rooms).\64\ These exposures were then
compared with the cardiotoxic LOAEL for 2-BTP. All but one modeled 7.5-
minute and 15-minute exposures for varying ventilation rates were lower
than the LOAEL of 10,000 ppm for 2-BTP. The estimated exposures were
derived using conservative assumptions (i.e., no mechanical
ventilation) and represent a worst-case scenario with a low probability
of occurrence. Because anticipated exposures could exceed the exposure
limit for 2-BTP, EPA recommends that standard safety techniques to
ensure safety during the use of 2-BTP fire extinguishers be followed in
non-residential locations. 2-BTP handheld extinguishers should follow
required minimum room volumes established by UL 2129, Halocarbon Clean
Agent Fire Extinguishers,\65\ when discharged into a confined space.
This standard prohibits the exceedance of the cardiotoxic LOAEL for any
fire suppressant (i.e., 10,000 ppm or 1.0% for 2-BTP). Therefore, per
UL 2129, a warning label for 2-BTP extinguishers will mitigate use in
confined spaces. Based on the above results, 2-BTP is not expected to
pose significant risk to end users when used as a streaming fire
extinguishing agent in non-residential applications, except for
commercial home office and personal watercraft. EPA provides additional
information on safe use of this substitute for establishments
manufacturing, installing and maintaining equipment using this agent in
the ``Further Information'' column of the regulatory listing. Since
this additional information is not part of the regulatory decision
under SNAP, these statements are not binding for use of the substitute
under the SNAP program. While the items listed are not legally binding
under the SNAP program, EPA encourages users of substitutes to apply
all statements in the ``Further Information'' column in their use of
this substitute as best practices for safer use.
---------------------------------------------------------------------------

    \64\ ICF, 2022r. Risk Screen on Substitutes as Streaming Agents
in Non-Residential Applications. Substitute: 2-bromo-3,3,3-
trifluoropropene (2-BTP).
    \65\ UL, 2017. Standard 2129--Halocarbon Clean Agent Fire
Extinguishers. Edition 3. This document is accessible at: https://www.shopulstandards.com/ProductDetail.aspx?UniqueKey=32182.
---------------------------------------------------------------------------

    Comparison to other fire suppressants: 2-BTP has an ODP of 0.0028,
comparable to other listed substitutes in this end-use, with ODPs
ranging from zero to 0.022. 2-BTP has a GWP of 0.23-0.26, which for
streaming agents is lower than or comparable to that of other
acceptable substitutes, with GWPs that range from about zero to 9,810.
2-BTP is considered a VOC and is not excluded from EPA's regulatory
definition of VOC (see 40 CFR 51.100(s)) for the purpose of addressing
the development of SIPs to attain and maintain the NAAQS. Other
acceptable fire suppression agents currently in use in this end-use are
also VOC (e.g., C6-perfluoroketone), and 2-BTP is
anticipated to pose no greater risk than other alternatives listed as
acceptable in this end-use. Toxicity risks can be minimized by use
consistent with the NFPA 10 Standard for Portable Fire Extinguishers,
recommendations in the SDS, and other safety precautions common in the
fire suppression industry.
    EPA is finalizing listing 2-BTP as acceptable, subject to use
conditions, as a streaming agent for use in non-residential
applications, except for commercial home office and personal
watercraft, because the overall environmental and human health risk
posed by the substitute is lower than or comparable to the overall risk
posed by other alternatives listed as acceptable in the same end-use.
4. What use conditions is EPA finalizing?
    EPA is finalizing listing 2-BTP as acceptable, subject to use
conditions. The use conditions are for use in normally unoccupied
spaces under 500 ft\3\ in total flooding fire suppression systems, and
as a streaming agent for use in non-residential applications, except
for commercial home offices and personal watercraft.
5. Why is EPA finalizing these specific use conditions?
    EPA is finalizing listing 2-BTP as acceptable, subject to use
conditions, for use only in normally unoccupied spaces under 500 ft\3\
in total flooding fire suppression systems. These space limitations are
consistent with additional information submitted to EPA. The
limitations correspond to use in small, enclosed spaces, such as an
electrical closet. Such spaces would require a smaller amount of fire
suppressant, reducing potential exposures to workers and the general
public and reducing potential toxicity risks.
    Additionally, EPA is finalizing listing 2-BTP as acceptable subject
to use conditions as a streaming agent for use

in non-residential applications, except for commercial home office and
personal watercraft. The definition of ``residential use'' in the SNAP
regulations at 40 CFR 82.172 is use by a private individual of a
chemical substance or any product containing the chemical substance in
or around a permanent or temporary household, during recreation, or for
any personal use or enjoyment. Use within a household for commercial or
medical applications is not included in this definition, nor is use in
automobiles, watercraft, or aircraft. Use in a commercial home office
or in personal watercraft could result in exposure to members of the
general public, including sensitive individuals such as children or the
elderly. In addition, air exchange is often lower in a commercial home
office or a personal watercraft than in industrial or other commercial
applications, potentially resulting in higher exposure levels than in
those other non-residential applications. Because of the more sensitive
populations and potentially higher exposures associated with those
applications, EPA is finalizing listing 2-BTP for use in non-
residential applications other than commercial home office and personal
watercraft.
6. How is EPA responding to comments on 2-BTP?
    EPA received one comment on the 2-BTP section of the proposed rule.
The commenter supported finalizing the rule as proposed.
    Comment: American Pacific, the manufacturer of 2-BTP, indicated
they ``[s]upport [the proposed rule] findings and conclusions with
respect to the 2-BTP clean fire extinguishant.''
    Response: EPA acknowledges the support for this proposed listing,
and for the reasons discussed above, we are finalizing this listing as
proposed.

H. Total Flooding Fire Suppression--Listing of EXXFIRE [supreg] as
Acceptable, Subject to Use Conditions, for Use in Normally Unoccupied
Spaces

1. What is EPA's final listing decision for EXXFIRE [supreg]?
    As proposed, EPA is finalizing listing EXXFIRE [supreg] as
acceptable, subject to use conditions, for use in total flooding fire
suppression systems in normally unoccupied spaces. EPA received no
comments relating to the proposed listing of EXXFIRE [supreg]. Prior to
activation, the EXXFIRE [supreg] formulation is in solid form and
contained within a hermetically sealed steel container. Upon detection
of a fire, nitrogen gas is released from the unit. The nitrogen gas
dilutes the oxygen level within the enclosure, and consequently
suppresses the fire. After activation, only gas components exit the
casing. All solid products remain inside the casing before, during and
after activation. Use of this agent should be in accordance with the
safety guidelines in the latest edition of the NFPA 2001 standard.
    The redacted submission and supporting documentation for EXXFIRE
[supreg] are provided in the docket for this proposed rule (EPA-HQ-OAR-
2021-0836) at https://www.regulations.gov. EPA performed an assessment
to examine the health and environmental risks of each of this
substitute. This assessment is available in the docket for this
rule.\66\
---------------------------------------------------------------------------

    \66\ ICF, 2022s. Risk Screen on Substitutes in Total Flooding
Systems in Normally Unoccupied Spaces; Substitute: EXXFIRE [supreg].
---------------------------------------------------------------------------

2. What is EXXFIRE [supreg] and how does it compare to other fire
suppressants in the same end-use?
    Environmental information: According to the submitter, the active
ingredients for this technology are nonvolatile solids before
activation so the ODP, atmospheric lifetime, and GWP are all zero. The
gaseous post-activation products that are released upon activation of
the fire suppressant with GWPs are carbon monoxide (CO),
CO2, and various hydrocarbons with GWPs ranging from less
than one to 25; however, these compounds are present in trace amounts,
together making up less than 0.5 percent of the total weight of the
post-activation products. The majority of the post-activation
constituents of EXXFIRE [supreg] are either not organic (e.g.,
nitrogen, oxygen, water, hydrogen) or are excluded from EPA's
regulatory definition of VOC (see 40 CFR 51.100(s)), for the purpose of
addressing the development of SIPs to attain and maintain the NAAQS.
Some constituents of EXXFIRE [supreg] are considered VOC and are not
excluded from EPA's regulatory definition of VOC (see 40 CFR
51.100(s)), including a variety of hydrocarbons; however, these
compounds are present in trace amounts.
    Flammability information: EXXFIRE [supreg] post-activation products
are non-flammable, except for certain hydrocarbons that are present in
trace amounts.
    Toxicity and exposure data: EPA assessed potential health risks
from exposure. Most post-activation products for EXXFIRE [supreg] are
not expected to result in adverse health effects; however, due to the
potential presence of lithium fluoride, which is acutely toxic upon
inhalation or ingestion and can cause serious skin, eye, and
respiratory tract irritation, the use of this system is only
recommended for use in normally unoccupied spaces. Although expected to
be maintained inside the generator, the potential presence of lithium
fluoride in the post-activation particulate products, justifies the
necessity for personnel to wear proper PPE (i.e., particulate-removing
respirator with NIOSH type N95 or better filters) upon reentry into the
space following a discharge of the system to mitigate those risks. The
submitter indicates that the proposed substitute can reduce oxygen
levels to 10 to 12 percent, which can cause a potential asphyxiation
hazard.
    EPA evaluated occupational and general population exposure at
manufacture of EXXFIRE [supreg] systems and at end use to ensure that
the use of EXXFIRE [supreg] will not pose unacceptable risks to workers
or the general public. Exposure is possible upon reentry into a space
after a system has been discharged. Protective gloves, tightly sealed
goggles, protective work clothing, and particulate-removing respirators
should be worn for installation and servicing activities, to protect
workers in any event of potential discharge of the substitute,
accidental or otherwise. Filling or servicing operations should be
performed in well-ventilated areas. Toxicity risks can be minimized by
use consistent with the NFPA 2001 standard, recommendations in the SDS,
and other safety precautions common in the fire suppression industry.
EPA provides additional information on safe use of this substitute for
establishments manufacturing, installing and maintaining equipment
using this agent in the ``Further Information'' column of the
regulatory listing. Since this additional information is not part of
the regulatory decision under SNAP, these statements are not binding
for use of the substitute under the SNAP program. While the items
listed are not legally binding under the SNAP program, EPA encourages
users of substitutes to apply all statements in the ``Further
Information'' column in their use of this substitute as best practices
for safer use.
    Comparison to other fire suppressants: EXXFIRE [supreg] has an ODP
of zero, comparable to other listed substitutes in this end-use, with
ODPs ranging from zero to 0.048. For total flooding agents, EXXFIRE
[supreg] has a GWP of zero prior to activation (and one to 25 for
certain post-activation products present in trace amounts), which is
comparable to or lower than that of other acceptable substitutes, such
as HFC-227ea and other substitutes with

GWPs up to 22,800.\67\ The majority, approximately 99.5 percent, of the
post-activation constituents of EXXFIRE [supreg] are either not organic
or are excluded from EPA's regulatory definition of VOC (see 40 CFR
51.100(s)), for the purpose of addressing the development of SIPs to
attain and maintain the NAAQS. EXXFIRE [supreg] is anticipated to pose
no greater risk than other alternatives listed as acceptable in this
end-use. Toxicity risks can be minimized by use consistent with the
NFPA 2001 standard, recommendations in the SDS, and other safety
precautions common in the fire suppression industry. The potential
toxicity risks due to inhalation exposure are common to many total
flooding agents, including those already listed as acceptable under
SNAP for this same end-use. EXXFIRE [supreg]'s post-activation products
are nonflammable, as are all other available total flooding agents.
---------------------------------------------------------------------------

    \67\ For SF6, the substitute with the highest GWP,
the SNAP listing finds SF6 as ``acceptable subject to
narrowed use limits.''
---------------------------------------------------------------------------

    EPA is finalizing listing EXXFIRE [supreg] as acceptable, subject
to use conditions, in the end-use listed above because it does not pose
greater overall environmental and human health risk than other
available substitutes in the same end-use.
3. What use conditions is EPA finalizing and why?
    Consistent with the request by the submitter, and information we
have available at this time for our review, the use condition requires
that EXXFIRE [supreg] be used in total flooding fire suppression
systems only in areas that are not normally occupied. EPA conducted
this evaluation for use only in unoccupied spaces, and information was
provided by the submitter in the SNAP application specific for this
type of space based on EPA guidance.\68\ EPA needs additional
information, such as additional toxicity test information, to issue a
listing for normally occupied spaces, compared to a listing for
normally unoccupied spaces. This is because of the greater risk that
workers or members of the general public may be exposed if a fire
suppressant is used in normally occupied spaces. In the absence of such
information, as described in EPA's guidance, EPA issues listings for
powdered aerosol fire suppressants as acceptable subject to use
conditions for use in normally unoccupied spaces only.
---------------------------------------------------------------------------

    \68\ EPA, 2004. A Guide to Completing a Risk Screen: Collection
and Use of Risk Screen Data. Fire Suppression Sector. April 2004.
---------------------------------------------------------------------------

4. How is EPA responding to comments on EXXFIRE [supreg]?
    No comments were received regarding EPA's proposed listing for
EXXFIRE [supreg], and for the reasons explained above EPA is finalizing
this listing as proposed.

I. Total Flooding Fire Suppression--Listing of Powdered Aerosol H
(Pyroquench-[alpha] TM) as Acceptable, Subject to Use
Conditions, for Use in Normally Unoccupied Spaces

1. What is EPA's final listing decision for Powdered Aerosol H?
    As proposed, EPA is finalizing listing Powdered Aerosol H, also
known as Pyroquench-[alpha] TM, as acceptable, subject to
use conditions, for use in total flooding fire suppression systems in
normally unoccupied spaces. EPA received no comments relating to the
proposed listing of Powdered Aerosol H. Prior to activation, the
Powdered Aerosol H formulation is contained as a solid disk of
chemicals in insulated and dual-sealed casings. In response to heat and
lack of oxygen, the formulation undergoes a chemical reaction; once the
Powdered Aerosol H system is activated, it generates and discharges a
homogenous mixture of gas and particulates into a space containing a
fire hazard or directly on the hazard itself, extinguishing the fire.
In the ``Further Information'' column of the tables at the end of this
document, we state that use of this agent should be in accordance with
the safety guidelines in the latest edition of the NFPA 2010 Standard
for Fixed Aerosol Fire Extinguishing Systems.
    The redacted submission and supporting documentation for Powdered
Aerosol H are provided in the docket for this final rule (EPA-HQ-OAR-
2021-0836) at https://www.regulations.gov. EPA performed an assessment
to examine the health and environmental risks of each of this
substitute. This assessment is available in the docket for this final
rule.69 70
---------------------------------------------------------------------------

    \69\ ICF, 2022t. Risk Screen on Substitutes in Total Flooding
Systems in Normally Unoccupied Spaces; Substitute: Pyroquench-
[alpha]TM.
    \70\ ICF, 2023b. Risk Screen on Substitutes in Total Flooding
Systems in Normally Unoccupied Spaces; Substitute: Pyroquench-
[alpha]TM.
---------------------------------------------------------------------------

2. What is Powdered Aerosol H and how does it compare to other fire
suppressants in the same end-use?
    Environmental information: According to the submitter, the active
ingredients for this technology are nonvolatile solids before
activation so the ODP, atmospheric lifetime, and GWP are all zero. The
gaseous post-activation products that are released upon activation of
the fire suppressant with GWPs are nitrogen dioxide (NO2)
and CO2, with GWPs of close to zero 71 72 and
one, respectively. The post-activation constituents of Powdered Aerosol
H are excluded from EPA's regulatory definition of VOC (see 40 CFR
51.100(s)), for the purpose of addressing the development of SIPs to
attain and maintain the NAAQS.
---------------------------------------------------------------------------

    \71\ Myhre, et.al., 2013: Anthropogenic and Natural Radiative
Forcing. In: Climate Change 2013: The Physical Science Basis.
Contribution of Working Group I to the Fifth Assessment Report of
the Intergovernmental Panel on Climate Change [Stocker, T.F., D.
Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels,
Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge University Press,
Cambridge, United Kingdom and New York, NY, USA. Available online
at: https://www.ipcc.ch/report/ar5/wg1/.
    \72\ In the proposal for this rule, EPA incorrectly noted the
GWP for NO2 as 120. EPA is correcting the GWP and
citation in this final rule. This correction does not change EPA's
listing of acceptable, subject to use conditions, as set forth in
the rule, for use of Powdered Aerosol H in fire protection.
---------------------------------------------------------------------------

    Flammability information: Powdered Aerosol H post-activation
products are non-flammable.
    Toxicity and exposure data: EPA assessed potential health risks
from exposure to the proposed substitute as a total flooding agent in
normally unoccupied spaces. Because the pre-activation components of
the fire suppressant are prepared in tablets that are non-reactive and
do not crumble or flake, there is no concern regarding inhalation or
ingestion of the pre-activation compounds. The discharge of the
powdered aerosol after activation results in temporary reduced
visibility in the protected space due to the uniform distribution of
the particulate generated and may cause ocular, dermal, and respiratory
irritation. EPA recommends that workers not enter the space following
discharge until all particles have settled and the gases released by
the total flooding system have dissipated. Use according to the NFPA
2010 Standard will reduce any safety risks due to reduced visibility.
The use of proper PPE, such as protective clothing, gloves, goggles,
and particulate-removing respirators, during manufacturing, at
installation, maintenance, and clean-up, minimizes personnel exposure
from inhalation of the substitute. EPA provides additional information
on safe use of this substitute for establishments manufacturing,
installing and maintaining equipment using this agent in the ``Further
Information'' column of the regulatory listing. Since this additional
information is not part of the regulatory decision under SNAP, these

statements are not binding for use of the substitute under the SNAP
program. While the items listed are not legally binding under the SNAP
program, EPA encourages users of substitutes to apply all statements in
the ``Further Information'' column in their use of this substitute as
best practices for safer use.
    EPA expects that procedures identified in the SDS for Powdered
Aerosol H and good manufacturing practices will be adhered to, and that
the appropriate safety and personal PPE consistent with OSHA guidelines
will be used during installation, servicing, post-discharge clean-up
and disposal of total flooding systems using Powdered Aerosol H. The
manufacturer guidance upon installation of the system provides the
appropriate time after which workers may re-enter the area for disposal
to allow the maximum settling of all particulates.
    Comparison to other fire suppressants: The post-activation products
of Powdered Aerosol H have an ODP of zero, comparable to or lower than
other listed substitutes in this end-use, with ODPs ranging from zero
to 0.048. For total flooding agents, Powdered Aerosol H's GWP of zero
prior to activation (and close to zero and one for certain post-
activation products) is comparable to or lower than that of other
acceptable substitutes, such as HFC-227ea and other substitutes with
GWPs up to 22,800.\73\ Other acceptable substitutes in this end-use
have comparable GWPs ranging from zero to one, such as water, inert
gases, and other powdered aerosol fire suppressants. Toxicity risks can
be minimized by use consistent with the NFPA 2010 standard,
recommendations in the SDS, and other safety precautions common in the
fire suppression industry. The potential toxicity risks due to
inhalation exposure are common to many total flooding agents, including
those already listed as acceptable under SNAP for this same end-use.
Powdered Aerosol H's post-activation products are nonflammable, as are
all other available total flooding agents.
---------------------------------------------------------------------------

    \73\ For SF6, the substitute with the highest GWP,
the SNAP listing finds SF6 as ``acceptable subject to
narrowed use limits.''
---------------------------------------------------------------------------

    EPA is finalizing listing Powdered Aerosol H as acceptable, subject
to use conditions, in the end-use listed above because it does not pose
greater overall environmental and human health risk than other
available substitutes in the same end-use.
3. What use conditions is EPA finalizing and why?
    Consistent with the submitter's request, and information we have
available at this time for our review, EPA finalizes the use condition
that Powdered Aerosol H be used in total flooding fire suppression
systems only in areas that are not normally occupied. EPA conducted
this evaluation for use only in unoccupied spaces, and information was
provided by the submitter in the SNAP application specific for this
type of space based on EPA guidance.\74\ EPA needs additional
information, such as additional toxicity test information, to issue a
listing for normally occupied spaces, compared to a listing for
normally unoccupied spaces. This is because of the greater risk that
workers or members of the general public may be exposed to if a fire
suppressant is used in normally occupied spaces. In the absence of such
information, as described in EPA's guidance, EPA issues listings for
powdered aerosol fire suppressants as acceptable subject to use
conditions for use in normally unoccupied spaces only.
---------------------------------------------------------------------------

    \74\ EPA, 2004. A Guide to Completing a Risk Screen: Collection
and Use of Risk Screen Data. Fire Suppression Sector. April, 2004.
---------------------------------------------------------------------------

4. How is EPA responding to comments on Powdered Aerosol H?
    No comments were received regarding EPA's proposed listing for
Powdered Aerosol H, and for the reasons discussed above, EPA is
finalizing this section of the rulemaking as proposed.

J. How is EPA responding to other comments?

    Comment: Several commenters (AHRI, the Alliance, AHAM, Carrier,
EIA, Brigett Griffin, LG Electronics, Chemours, and Trane) noted
general support for this rulemaking. Additionally, the Alliance and
AHAM stressed a desire for the Agency to issue a final rule in a timely
manner to ensure that lower GWP alternatives are available. Trane noted
their support for a transition to lower flammability ``A2L''
refrigerants.
    Response: EPA acknowledges the commenters' support of the listings
in this rulemaking. The Agency acknowledges Trane's support for listing
A2L refrigerants. EPA is finalizing many listing decisions as proposed
and is finalizing other listing decisions with relatively minor changes
that address and incorporate information provided in comments as
described throughout the preamble above.
    Comment: EIA commented on the GWP of HFC-32 and noted that
refrigerants like HFC-32 have lower GWPs than the chemicals they
replace and are near-term solutions which help facilitate the reduction
in demand for HFCs under the American Innovation and Manufacturing
(AIM) Act of 2020. EIA urged that EPA should consider restricting these
refrigerants in the future, once additional ultra-low GWP refrigerants
become more widely adopted.
    Response: EPA acknowledges EIA's concern for the GWPs of various
refrigerants and recognition that new alternatives will be more widely
adopted in the future. EPA plans to continue to review the GWPs of
substitutes consistent with the SNAP program criteria. EIA's comment on
the AIM Act is beyond the scope of this action.
    Comment: Diversified CPC International stated that EPA should
consider listing the ASHRAE A3 refrigerants R-290, R-600, R-600a, R-
601a, R-1270, and blends (i.e., propane, butane, isobutane, isopentane,
propylene, and blends) as acceptable to align with UL 60335-2-89, 2nd
Edition and UL 60335-2-40, 3rd Edition. Additionally, Diversified CPC
International and EIA stated that they hoped EPA will prioritize
adoption of revised use conditions for refrigeration equipment in a
future rule to take into account UL 60335-2-89, 2nd Edition, which
would include expanded charge limits for hydrocarbons up to 500 g in
self-contained equipment. EIA also stated that modernizing standards
for commercial refrigeration will open a pathway for companies to
significantly reduce climate impacts while maintaining safe systems.
ATMOsphere urged that EPA consider the impending use of hydrocarbons in
chillers, ACs and HPs and stated that such systems are becoming widely
used in Europe.
    Response: EPA acknowledges these comments expressing support for
hydrocarbons in the refrigeration and AC sector. EPA did not propose to
revise the current use conditions for R-290 or the hydrocarbon blend R-
441A for use in self-contained room ACs and HPs. The Agency also did
not propose to list R-290, R-600, R-600a, R-601a, R-1270, and blends
for use in other end-uses. Therefore, these comments are beyond the
scope of this rulemaking. The Agency may consider proposing additional
listings, including listings for hydrocarbons and other lower-GWP
refrigerants in commercial refrigeration in future rulemakings, in
addition to updating use conditions for existing hydrocarbon listings.
EPA

acknowledges that in other countries, refrigerants used in chillers may
differ from the United States. The Agency's review of substitutes
relies on the SNAP program criteria and the conditions in the United
States, not on whether a substitute is in use elsewhere.
    Comment: ATMOsphere urged the use of refrigerants such as
hydrocarbons, CO2, and ammonia in split-system AC, household
refrigerators, supermarket cases, HPs, HP water heaters, and chillers.
    Response: EPA acknowledges the increasing use of both fluorinated
and non-fluorinated alternatives to ODS. In this action, EPA did not
propose to list hydrocarbons, CO2, or ammonia and thus is
not finalizing such a listing in this final rule. The Agency intends to
consider proposing additional listings, including listings for non-
fluorinated alternatives, in future rulemakings.
    Comment: Savannah River Nuclear Solutions stated that EPA needs to
exempt the flammable refrigerants identified as being exempt from the
venting prohibition contained in 40 CFR 82.l54(a) from RCRA by adding
language to 40 CFR 261.2 and/or 40 CFR 261.4. This commenter stated
that the lack of exemption in 40 CFR 261.2 and/or 40 CFR 261.4 has
resulted in confusion on EPA's position with respect to RCRA regulation
of flammable refrigerants that are exempted under 40 CFR 82.154(a) from
the venting prohibition. Savannah River Nuclear Solutions noted that
the refrigerants in the end-uses described at Subpart G, Appendix R,
Items l, 2, 5 and 6 in the July 28, 2022 NPRM are exempt from the
venting prohibition contained in 40 CFR 82.l54(a) and in this text,
there is no indication the recovery or disposal of these refrigerants
in these end uses are hazardous waste under RCRA even when venting
occurs in a non-household setting. This commenter cited from multiple
rulemakings that exempted certain refrigerants from the venting
prohibition under CAA section 608(c)(2).
    Response: EPA did not open for comment the listings 1 through 6 in
appendix R to 40 CFR part 82, subpart G mentioned by the commenter.
Rather, those entries were republished ``to bring the table in line
with the Office of the Federal Register's general requirement for
orderly codification by: adding entry numbers, replacing prohibited
language, and properly formatting the footnotes.'' (87 FR at 45509;
July 28, 2022). Similarly, EPA did not reopen the regulations at 40 CFR
261.2 and 40 CFR 261.4 through the NPRM. For these reasons, EPA
considers the comment to be outside of the scope of this rulemaking.
    In light of the commenter's statement about confusion regarding the
RCRA regulation of flammable refrigerants that are exempted under 40
CFR 82.154(a) from the venting prohibition, we note that we have
already addressed the applicability of RCRA to spent refrigerants in a
previous SNAP rule, which states, for example, that ``propane and other
HCs being recovered, vented, released, or otherwise disposed of from
commercial and industrial appliances are likely to be hazardous waste
under RCRA (see 40 CFR parts 261 through 270).'' (See 81 FR at 86799-
86800, December 1, 2016, for additional information).
    Comment: ATMOsphere, EIA, and an anonymous member of the public
commented on the atmospheric decomposition of HFC-134a and HFO-1234yf
into trifluoroacetic acid (TFA). ATMOsphere stated that TFA is
collecting in the environment, and EIA claimed that ``the presence of
persistent fluorinated by-products of HFCs and HFOs is increasing in
the environment,'' citing studies finding increasing levels of TFA in
ice cores,\75\ rainwater,\76\ groundwater,\77\ and leaf samples.\78\
All three commenters expressed concern about the potential risks TFA
might pose to human health and the environment. EIA asserted, ``it is
reasonable to conduct a complete review of these chemicals rather than
allow their continued proliferation,'' and suggested that EPA should
evaluate the potential risks from TFA through future SNAP regulations.
---------------------------------------------------------------------------

    \75\ Chemical and Engineering News, May 1, 2020. ``CFC
replacements are a source of persistent organic pollution in the
Arctic.'' K. Bourzic. Available online at: https://cen.acs.org/environment/persistent-pollutants/CFC-replacements-source-persistent-organic/98/web/2020/05.
    \76\ Freeling et al., 2020. F. Freeling, D. Behringer, F.
Heydel, M. Scheurer, T. Ternes, and K. N[ouml]dler.
``Trifluoroacetate in Precipitation: Deriving a Benchmark Data Set''
Environ. Sci. Technol. 2020, 54, 18, 11210-11219. August 17, 2020.
Available online at: https://pubs.acs.org/doi/10.1021/acs.est.0c02910.
    \77\ Zihan Zhai et al., 2015. Zihan Zhai, Jing Wu, Xia Hu, Li
Li, Junyu Guo, Boya Zhang, Jianxin Hu, and Jianbo Zhang. ``A 17-fold
increase of trifluoroacetic acid in landscape waters of Beijing,
China during the last decade,'' Chemosphere. 2015 Jun; 129:110-7.
doi: 10.1016/j.chemosphere.2014.09.033. Abstract available online at
https://pubmed.ncbi.nlm.nih.gov/25262947/.
    \78\ Freeling et al., 2022. F. Freeling, M. Scheurer, J.
Koschorreck, G. Hoffmann, T.A. Ternes, and K. N[ouml]dler. ``Levels
and Temporal Trends of Trifluoroacetate (TFA) in Archived Plants:
Evidence for Increasing Emissions of Gaseous TFA Precursors over the
Last Decades,'' Environ. Sci. Technol. Lett. 2022, 9, 5, 400-405.
April 18, 2022. Available online at: https://pubs.acs.org/doi/10.1021/acs.estlett.2c00164.
---------------------------------------------------------------------------

    Response: EPA appreciates the information provided by EIA on the
atmospheric decomposition of HFO-1234yf to TFA. We note that several
studies and reports provide further information about this topic. A
2014 study by Kazil, et al. analyzed TFA deposition in the United
States assuming 100 percent of all motor vehicle air conditioning
(MVAC) systems use HFO-1234yf, which was the largest use of HFO-1234yf
at that time.\79\ The results indicated that rainwater TFA
concentrations, while varying strongly geographically, will on average
be low compared to the levels at which toxic effects are observed in
aquatic systems. Similarly low TFA concentrations were estimated for
emissions of HFO-1234yf from Asia in a 2021 study by David, et al.\80\
The World Meteorological Organization also provided a summary of key
information pertaining to TFA in their 2022 report to the Montreal
Protocol.\81\ The report states:
---------------------------------------------------------------------------

    \79\ Kazil et al., 2014. ``Deposition and rainwater
concentrations of trifluoroacetic acid in the United States from the
use of HFO-1234yf'' J. Kazil, S. McKeen, S.-W. Kim, R. Ahmadov, G.A.
Grell, R.K. Talukdar, A.R. Ravishankara. JGR Atmospheres. Volume
119, Issue 24. December 27, 2014. Pages 14,059-14,079. October 31,
2014. Available online at https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2014JD022058.
    \80\ David et al., 2021. ``Trifluoroacetic acid deposition from
emissions of HFO-1234yf in India, China, and the Middle East,''
Volume 21, issue 19. Atmos. Chem. Phys., 21, 14833-14849, 2021.
https://doi.org/10.5194/acp-21-14833-2021. Available online at
ttps://acp.copernicus.org/articles/21/14833/2021/.
    \81\ World Meteorological Organization (WMO), 2022. Executive
Summary. Scientific Assessment of Ozone Depletion: 2022, GAW Report
No. 278, 56 pp.; WMO: Geneva, 2022. Available online at https://ozone.unep.org/system/files/documents/Scientific-Assessment-of-Ozone-Depletion-2022-Executive-Summary.pdf.

    The formation in the atmosphere of trifluoroacetic acid (TFA) is
expected to increase in the coming decades due to increased use of
HFOs and HCFOs. TFA, a breakdown product of some HFCs, HCFCs, HFOs
and HCFOs, is a persistent chemical with potential harmful effects
on animals, plants, and humans. The concentration of TFA in
rainwater and ocean water is, in general, significantly below known
toxicity limits at present. Potential environmental impacts of TFA
---------------------------------------------------------------------------
require future evaluation due to its persistence. (p. 14)

    Most TFA currently found in the environment resulting from
decomposition of refrigerants likely derived from HFC-134a, which is
being phased down and the use of which is anticipated to decrease in
end-uses where safer alternatives are found acceptable under the SNAP
program. EPA also notes that the modeling studies referenced generally
assume a one-to-one substitution of HFO-1234yf for HFC-134a to be
conservative;

however, none of the end-uses in this final rule where HFO-1234yf is
being listed as acceptable are anticipated to cause a one-for-one
transition from HFC-134a to HFO-1234yf. Any increase in TFA deposition
due to this rule is expected to be less than the modeled increases in
TFA from studies that found the levels of TFA in the environment
remained, ``too small to be a risk to the environment over the next few
decades.'' Use of HFO-1234yf and concerns about TFA in applications not
addressed by this final rule are outside the scope of this rulemaking.
    There are ongoing evaluations of the potential risks of TFA
exposure. In 2020, the Environmental Effects Assessment Panel (EEAP) to
the Montreal Protocol released an update \82\ to its report on the
environmental effects of stratospheric ozone depletion, UV radiation,
and interactions with climate change, including the potential effects
of TFA from ODS and their substitutes. That report noted that TFA ``has
a no-observed-effect-concentration (NOEC) for aquatic species, which is
typically >10,000 [mu]g/L,'' while ``analysis of 1187 samples of
rainwater collected in eight locations across Germany in 2018-2019
showed median and a precipitation-weighted mean concentration of TFA of
0.210 [mu]g/L and 0.335 [mu]g/L, respectively,'' and ``another recent
paper reported TFA . . . in precipitation in the low [mu]g/L range
across 28 cities in mainland China.'' These studies and others led the
EEAP to state, ``Trifluoroacetic acid continues to be found in the
environment, including in remote regions, although not at
concentrations likely to have adverse toxicological consequences.''
---------------------------------------------------------------------------

    \82\ EEAP, 2020. ``Environmental effects of stratospheric ozone
depletion, UV radiation, and interactions with climate change: UNEP
Environmental Effects Assessment Panel, Update 2020.'' Photochemical
& Photobiological Sciences https://doi.org/10.1007/s43630-020-00001-x. Available online at: https://engineering.case.edu/centers/sdle/sites/engineering.case.edu.centers.sdle/files/neale_et_al._-_2021_-_environmental_effects_of_stratospheric_ozone_deple.pdf.
---------------------------------------------------------------------------

    In its 2021 Summary Update for Policymakers,\83\ the EEAP stated:
---------------------------------------------------------------------------

    \83\ EEAP, 2021. ``Summary Update 2021 for Policymakers'' UNEP
Environmental Effects Assessment Panel. Available online at: https://ozone.unep.org/sites/default/files/assessment_panels/EEAP-summary-update-2021-for-policymakers.pdf.

    TFA likely has natural geochemical sources, is widely used in
industry and research laboratories, and is a by-product of the
synthesis and degradation of fluorinated and perfluorinated
compounds (PFCs). . . . TFA has recently been found in
precipitation, surface waters, and indoor dust in China . . .,
although concentrations are below those considered toxic. No
additional studies on the toxicity of TFA to organisms have been
reported, but prior research has shown that this compound is not
highly toxic to mammals and aquatic organisms, although some plants
and algae may be sensitive. . . . At present, it is not possible to
quantify the proportion of anthropogenic sources of TFA resulting
from substances not falling under the purview of the Montreal
Protocol, but available evidence indicates that this breakdown
product is of minimal risk to human health. (p. 10; references in
---------------------------------------------------------------------------
the text omitted here)

    In response to EIA's suggestion that EPA evaluate potential risks
from TFA through future SNAP rules, EPA notes that it does consider
ecotoxicity as a criterion when evaluating alternatives under SNAP's
comparative risk framework, and the Agency has considered the potential
impacts of TFA in past actions that found HFO-1234yf acceptable in
certain end-uses. For example, EPA studied the potential generation of
TFA when first listing neat (i.e., 100%, not in blends) HFO-1234yf as
acceptable, subject to use conditions, in motor vehicle air
conditioning. The myriad studies EPA referenced all concluded that the
additional TFA from HFO-1234yf did not pose a significant additional
risk, even if it were assumed to be used as the only refrigerant in all
refrigeration and air conditioning equipment (76 FR 17492-17493, March
29, 2011). The Agency intends to continue its approach to evaluating
the potential risks from TFA in future SNAP regulations. Based on
current information, EPA does not consider the overall risk to human
health and the environment due to the listings in this final rule to be
significantly greater than for other available or potentially available
substitutes for the same uses.
    Comment: Three commenters (ATMOsphere, EIA, and an anonymous
commenter) expressed concern about per- and poly-fluoroalkyl substances
(PFAS). Commenters noted that under some definitions of PFAS, HFCs and
HFOs discussed in this rule are considered PFAS, and two of the
commenters suggested EPA should adopt a particular definition of PFAS.
The commenters noted that some PFAS chemicals, e.g., perfluorooctanoic
acid (PFOA) and perfluorooctane sulfonate (PFOS), present risks to
human health and the environment.
    Response: EPA understands that currently, there is no single
commonly agreed definition of PFAS, and whether or not HFCs or HFOs are
classified as PFAS depends on the definition being used. EPA's PFAS
roadmap, available at https://www.epa.gov/pfas, sets timelines for
specific actions and outlines EPA's commitments to new policies to
safeguard public health, protect the environment, and hold polluters
accountable. This rule does not in any way establish a definition of
PFAS, nor do the listing decisions depend on a specific definition. In
evaluating alternatives using its comparative risk framework, SNAP
already considers potential risks to human health and the environment.
Regardless of what definition of PFAS is used, not all PFAS are the
same in terms of toxicity or any other risk. Some PFAS have been shown
to have extremely low toxicity, for example. If a chemical has been
found to present lower overall risk to human health or the environment,
it might be found acceptable under SNAP regardless of whether or not it
falls under a particular definition of PFAS. Likewise, SNAP might not
find a potential alternative acceptable if it presented greater overall
risk, regardless of whether or not it falls under a particular
definition of PFAS. As described in the risk screens for alternatives
found in the docket for this rulemaking, potential risk to human health
or the environment has been considered directly for each chemical, and
the risks are not assumed to follow from a chemical falling into any
particular category of substances.

III. Statutory and Executive Order Reviews

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

    This action is not a significant regulatory action and was
therefore not submitted to the Office of Management and Budget (OMB)
for review.

B. Paperwork Reduction Act (PRA)

    OMB has previously approved the information collection activities
contained in the existing regulations and has assigned OMB control
number 2060-0226. The approved Information Collection Request includes
five types of respondent reporting and recordkeeping activities
pursuant to SNAP regulations: submission of a SNAP petition, filing a
Toxic Substances Control Act (TSCA)/SNAP Addendum, notification for
test marketing activity, recordkeeping for substitutes acceptable
subject to use restrictions, and recordkeeping for small volume uses.
This action does not impose a new information collection burden under
the PRA because the existing Information Collection Request already
includes recordkeeping for substitutes acceptable subject to use
restrictions--i.e., acceptable subject to

use conditions or acceptable subject to narrowed use limits.

C. Regulatory Flexibility Act (RFA)

    I certify that this action will not have a significant economic
impact on a substantial number of small entities under the RFA. In
making this determination, EPA concludes that the impact of concern for
this rule is any significant adverse economic impact on small entities
and that the agency is certifying that this rule will not have a
significant economic impact on a substantial number of small entities
because the rule has no net burden on the small entities subject to the
rule. This action adds the additional options under SNAP of using HFC-
32, HFO-1234yf, R-452B, R-454A, R-454B, R-454C, R-1150, 2-BTP, EXXFIRE
[supreg], and Powdered Aerosol H, in the specified end-uses, but does
not mandate such use. Users who choose to avail themselves of this
flexibility for R-1150 must make a reasonable effort to ascertain that
other substitutes or alternatives are not technically feasible and must
document and keep records of the results of such investigations.
Because equipment for HFC-32, HFO-1234yf, R-452B, R-454A, R-454B, and
R-454C is not manufactured yet in the U.S. for the chillers and
residential dehumidifiers end-uses, no change in business practice is
required to meet the use conditions, resulting in no adverse impact
compared with the absence of this rule. Similarly, R-1150, 2-BTP,
EXXFIRE [supreg], and Powdered Aerosol H are listed as acceptable with
use conditions consistent with industry standards and with the intended
uses described by the submitters, also requiring no change in business
practices and resulting in no adverse impact compared with the absence
of this rule. The new use conditions for HFC-32 in self-contained room
ACs and HPs were requested by industry and allow use consistent with
the more recent standard, UL 60335-2-40, while also allowing continued
use with another existing standard, UL 484, until the consensus
standard setting organization sunsets that older standard; these would
allow for greater consistency in business practices for different types
of equipment using the same refrigerant while giving industry time to
transition between two industry standards. Equipment for HFC-32 already
manufactured prior to the effective date of this final rule would not
be affected. Self-contained room ACs and HPs using HFC-32 have been
subject to similar use conditions, and thus the updated requirements
result in no adverse impact compared with the absence of this rule.
Thus, the final rule will not impose new costs on small entities. We
have therefore concluded that this action will have no net regulatory
burden for any directly regulated small entities.

D. Unfunded Mandates Reform Act (UMRA)

    This action does not contain any unfunded mandate 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,