discusses the use conditions that would apply to all five end-uses in
section II.H. In summary, the common use conditions proposed include
the following: restricting the use of the refrigerant to new equipment
that is specifically designed for that refrigerant; use consistent with
the 2nd edition of UL 60335-2-89, 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, technicians, and first responders of potential
flammability hazards. The regulatory text of the proposed decisions
appears in tables at the end of this document.
    If the regulatory text is finalized as proposed, EPA would revise
the existing listing for R-290 in new self-contained commercial ice
machines in appendix V to 40 CFR part 82, subpart G. The proposed
regulatory text contains listing decisions for new self-contained
commercial ice machines in appendix V, as well as certain other
previous listings that EPA is republishing for purposes of formatting
for the Federal

Register; EPA is not proposing substantive changes to, and is not
taking comment on, those earlier decisions (i.e., listings for R-290 in
new water coolers and in new very low temperature refrigeration
equipment).
1. Background on commercial ice machines
    See section II.C.1 for background on this end-use.
2. What are the ASHRAE classifications for refrigerant flammability?
    ASHRAE 34-2022 categorizes R-290 as being in the A3 Safety Group.
See section II.A.2 for further discussion on ASHRAE classifications.
3. What is R-290 and were is there information on its use in this end-
use?
    See section II.B.3 for further discussion on the identity,
environmental, flammability, toxicity, and exposure information for R-
290.
    Redacted submissions and supporting documentation for R-290 are
provided in the docket for this proposed rule (EPA-HQ-OAR-2023-0043) at
https://www.regulations.gov. EPA performed a risk screening assessment
to examine the health and environmental risks of this substitute in
self-contained commercial ice machines. The risk screen is available in
the docket for this proposed rule.\44\
---------------------------------------------------------------------------

    \44\ ICF, 2023q. Risk Screen on Substitutes in Commercial Ice
Machines (New Equipment); Substitute: (R-290).
---------------------------------------------------------------------------

4. What use conditions currently apply to this refrigerant in this end-
use?
    EPA previously listed R-290 acceptable, subject to use conditions,
in new self-contained commercial ice machines in SNAP Rule 21 (81 FR
86779, December 1, 2016). Those requirements are codified in appendix V
to 40 CFR part 82, subpart G. EPA provided information on the
environmental and health risks of R-290 and the various substitutes
available at that time for use in this end-use. Additionally, EPA's
previous risk screen for this refrigerant, based on the use conditions
in that rule, is available in the docket for that previous rulemaking
(EPA-HQ-OAR-2015-0663).
    R-290 has an ASHRAE classification of A3, indicating that it has
low toxicity and higher flammability. In the presence of an ignition
source (e.g., static electricity, a spark resulting from a closing
door, or a cigarette), an explosion or a fire could occur if the
concentration of R-290 were to exceed the LFL of 21,000 ppm (2.1
percent) by volume.
    The use conditions established in the 2016 listing for R-290 in new
self-contained commercial ice machines addressed safe use of this
flammable refrigerant and included the following: incorporation by
reference of Supplement SA to the 8th edition (July 31, 2009, including
revisions through November 29, 2013) of the standard UL 563, ``Ice
Makers''; refrigerant charge size limits based on cooling capacity and
type of equipment; and requirements for markings and warning labels on
equipment using the refrigerant to inform consumers, technicians, and
first responders of potential flammability hazards. Our assessment and
listing decisions in SNAP Rule 21 (81 FR 86779, December 1, 2016) found
that with the use conditions, the overall risk of this substitute,
including the risk due to flammability, was not significantly greater
risk in this end-use than other substitutes that are currently or
potentially available for that same end-use.
5. What updates to the existing use conditions for commercial ice
machines is EPA proposing?
    EPA is proposing to update the use conditions that apply to R-290
in new self-contained commercial ice machines manufactured on or after
the effective date of any final rule based on this proposal. Several of
the updated use conditions proposed for use of R-290 in self-contained
commercial ice machines are common to those proposed for the stand-
alone units end-use in section II.B, and other are common to all five
end-uses in this proposed rule. Because of this similarity, EPA
discusses the use conditions that would apply to all five end-uses in
section II.H. For R-290 in self-contained commercial ice machines,
these are the only revised use conditions EPA is proposing. In summary,
with the updates proposed to the use conditions for new self-contained
commercial ice machines, the common use conditions proposed include the
following: restricting the use of the refrigerant to new equipment that
is specifically designed for that refrigerant; use consistent with the
2nd edition of UL 60335-2-89, 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, technicians, and first responders of potential
flammability hazards.
    If finalized as proposed, the use conditions in this action would
apply to new self-contained commercial ice machines manufactured on or
after the effective date of the final rule. Any final rule would not
apply to nor affect equipment manufactured before the effective date of
this action and manufactured in compliance with the SNAP use conditions
applicable at the time of manufacture as stipulated in SNAP Rule 21 and
appendix V to 40 CFR part 82, subpart G. EPA views equipment to be
manufactured at the date upon which the appliance's refrigerant circuit
is complete, the appliance can function, the appliance holds a full
refrigerant charge, and the appliance is ready for use for its intended
purposes. For new self-contained commercial ice machines, this occurs
at the factory. If this rule is finalized as proposed, new self-
contained commercial ice machines manufactured between January 3, 2017,
and the effective date of the final rule based on this proposal would
be required to meet the use conditions in SNAP Rule 21 (which took
effect January 3, 2017) and as listed in appendix V to 40 CFR part 82,
subpart G (in listing 1), including the use condition incorporating by
reference Supplement SA to the 8th edition of UL 563. Such products
would be permitted to be warehoused and sold through normal channels,
even if they are sold or installed after the effective date of any
final rule based on this proposed rule. Self-contained ice machines
using R-290 manufactured on or after the effective date of any final
rule based on this proposal through September 29, 2024, would be
required to meet the use conditions so finalized and listed in the
revisions to appendix V. Those use conditions would allow manufacturers
of new self-contained commercial ice machines using R-290 to follow
either UL 563 or UL 60335-2-89 from the effective date of any final
rule based on this proposal and would last through September 29, 2024.
On and after September 30, 2024, the use condition for use of R-290 in
equipment that meets UL 60335-2-89 only would apply under SNAP.
    EPA is proposing use conditions allowing new self-contained
commercial ice machines to be manufactured consistent with Supplement
SA of UL 563, up to and including September 29, 2024, which is the date
when UL is sunsetting UL 563. Therefore, during the time between the
effective date of any final rule based on this proposal and September
29, 2024, manufacturers would be allowed to follow either UL 563, 8th
Edition or UL 60335-2-89, 2nd Edition. EPA is proposing allowing
manufacturers to adhere to either

standard for this limited time because the Agency recognizes that
manufacturers may need time to make necessary changes including to
their product labels. The period during which manufacturers may follow
either standard should provide sufficient time for manufacturers to
transition from UL 563 to UL 60335-2-89. EPA proposes that, beginning
September 30, 2024, R-290 may only be used in new self-contained
commercial ice machines that meet all requirements in UL 60335-2-89 for
the purposes of the SNAP program. See section II.H.1 for further
discussion on the requirements of this standard that EPA is proposing
to incorporate by reference.
    In addition, we are proposing that manufacturers would need to
follow the set of use conditions that correspond with a specific UL
standard (i.e., when using UL 563, follow all existing use conditions
in listing 1 and when using UL 60335-2-89, follow all use conditions in
listing 3 in the proposed revisions to appendix V). After the
transition period ends, stand-alone units manufactured with R-290 would
need to follow UL 60335-2-89 for purposes of the SNAP program.
    EPA also notes that we are not proposing to change two use
conditions that currently apply, nor are we taking comment on those
other use conditions. The use conditions that restrict the use of R-290
to new equipment specifically designed for this refrigerant, and that
require red-colored markings at service ports, pipes, hoses, and other
devices through which the refrigerant is serviced, are current use
conditions for R-290 in new self-contained commercial ice machines.
    If the regulatory text is finalized as proposed, EPA would amend to
add use conditions that apply to R-290 in new self-contained commercial
ice machines manufactured on or after the effective date of the final
rule. Equipment manufactured before the effective date of the final
rule would not be affected by this action and would hence be subject to
the current use conditions included in appendix V.
6. How do the proposed use conditions for commercial ice machines
differ from the existing ones and why is EPA proposing to change the
use conditions?
    The updated use conditions EPA is proposing are similar to the ones
that exist today in appendix V to 40 CFR part 82, subpart G, for R-290
in this end-use. The proposed requirements that R-290 must be used in
new equipment only and that new self-contained commercial ice machines
must include red markings at service ports, pipes, hoses, and other
devices through which the refrigerant is serviced, are repeated in this
proposed listing. The revised use conditions concern incorporating by
reference the most recent U.S. national standard for commercial ice
machines and labeling requirements consistent with that new standard.
Self-contained commercial ice machines using R-290 manufactured before
the effective date of a final rule based on this proposal would not be
affected by the revised use conditions.
    Warning labels are required under EPA's current regulations, and
EPA is proposing to continue to require them, although with some
specific language changes. EPA is proposing warning labels that are
identical to those required as use conditions for the use of R-290 in
self-contained commercial ice machines. EPA finds that using a common
set of labels, similar to those from UL 60335-2-89, would aid in
compliance and could reduce burden for the industry, especially for a
manufacturer that uses more than one refrigerant. EPA is proposing that
the labels must be provided in letters no less than 6.4 millimeter (\1/
4\ inch) high and must be permanent, which is identical to the current
requirement for R-290 in self-contained commercial ice machines.
    EPA is proposing to update the standard incorporated by reference
in the use conditions, and after a transition period, replacing the
requirement to follow Supplement SA of the 8th edition of UL 563 with
the proposed requirement to adhere to the 2nd edition of UL 60335-2-89.
UL 60335-2-89 was developed in an open and consensus-based approach,
with the assistance of experts in the refrigeration and AC industry as
well as experts involved in assessing the safety of products. The
revision cycle for the 2nd edition, including final recirculation,
concluded with its publication on October 27, 2021. The 2021 standard
UL 60335-2-89 replaces the previously published version of several
standards, including UL 563, which had already been revised into an 8th
edition by that time. EPA was aware of the continuing progress of UL
Standards to address flammable refrigerants more appropriately. In this
document, we are proposing such a change knowing that UL is replacing
the standard to which such equipment is certified from UL 563 to the
newer UL 60335-2-89 as of September 30, 2024.
    To allow time for manufacturers of self-contained commercial ice
machines to transition between the current use condition using the 8th
edition of UL 563, and the new use condition using the 2nd edition of
UL 60335-2-89, EPA is proposing to allow R-290 to be used in self-
contained commercial ice machines manufactured either following UL 563
or UL 60335-2-89 during a transition period. We propose that transition
period would begin on the effective date of any final rule based on
this proposal and would last through September 29, 2024. It is EPA's
understanding that UL intends to sunset UL 563 on September 29, 2024,
and EPA is proposing to coordinate with that sunset date. Beginning
September 30, 2024, the use condition in effect would only allow R-290
to be used in new self-contained commercial ice machines that follow UL
60335-2-89. In addition, we are proposing that manufacturers would need
to follow the set of use conditions that correspond with a specific UL
standard (i.e., when using UL 563, follow all use conditions in listing
1 and when using UL 60335-2-89, follow all use conditions in listing 3
in the proposed revisions to appendix V).
    Incorporating UL 60335-2-89 by reference in a use condition would
allow the industry to manufacture and test refrigeration equipment
following the most recent standard, which provides additional
flexibility and safeguards when using flammable refrigerants. The
transition period when equipment may follow either UL standard would be
helpful in implementing any transitions needed or planned for
manufacturers, installers, and technicians. A manufacturer, who may
offer different products within this end-use with different
refrigerants, could use similar processes, such as in developing and
applying the warning labels required.
    Another proposed revision to the use conditions is the limit on
charge sizes. The current use conditions from SNAP Rule 21 require the
charge sizes from UL 563 calculated consistent with UL 563, with a
maximum charge size of 150 g allowed. The proposed revised use
conditions for equipment manufactured on or after the effective date of
any final rule would allow charge sizes calculated based on UL 60335-2-
89, which would allow charge sizes of R-290 up to approximately 500 g
for open equipment, 300 g for equipment with doors or drawers, or 115 g
for equipment near a pathway for egress. These changes would allow the
use of R-290 in larger equipment than previously and would provide more
options for industry, while maintaining safety.
    Because of the differences between UL 563 and UL 60335-2-89, EPA
performed a new risk screen for R-290 as a refrigerant in commercial
ice

machines.\45\ In this risk screen, EPA adjusted charge sizes to be
consistent with the larger charge sizes allowed for R-290 under UL
60335-2-89. The risk screen also considered the impact of mitigation
methods such as valves that would restrict the amount of refrigerant
that could be released. The updated risk screen found that
concentrations of R-290 still would not exceed the LFL when used
according to the proposed use condition and consistent with UL 60335-2-
89, and thus the proposed new use conditions would also address
potential flammability risks of using R-290.\46\ In addition, the risk
screen modeled the reasonable worst-case scenario of short-term
exposure (15-minute TWA) due to a catastrophic release of the charge.
Under this highly conservative scenario, the worst-case exposure was
still significantly lower than the ATEL of 50,000 ppm.\47\ For further
information, see the risk screen in the docket for this rulemaking.
---------------------------------------------------------------------------

    \45\ ICF, 2023q. Op. cit.
    \46\ Ibid.
    \47\ Ibid.
---------------------------------------------------------------------------

7. What additional information is EPA including in this proposed
listing?
    EPA is providing additional information related to this proposed
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.H.2 for
further discussion on what additional information EPA is including in
these proposed listings. EPA notes that the additional information is
similar to, but not identical with, the addition information in the
listing for R-290 in self-contained commercial ice machines in SNAP
Rule 21. EPA is proposing additional information consistent with that
included in the other proposed listings for stand-alone units in this
rule and consistent with that included in the listings for R-290 as
acceptable, subject to use conditions, in self-contained commercial ice
machines in Rule 21. 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.
8. On which topics is EPA specifically requesting comment?
    EPA is requesting comment on all aspects of the proposed updates to
the use conditions as discussed in this section II.D. EPA requests
comments on the proposed change in use conditions and if and how such
change would affect the safety of self-contained commercial ice
machines using R-290. EPA is requesting comment on the risk mitigation
offered by compliance with the current version of the standard proposed
as use conditions, i.e., UL 60335-2-89, the nature of updates proposed
for this standard, and the expected timeline for those updates. The
Agency also requests comment on allowing a transition period where
either of two sets of use conditions, including either UL 563 or UL
60335-2-89, may be followed and on the specific dates for the
transition period. EPA is requesting comment on the applicability of
the 2nd edition of UL 60335-2-89 to new self-contained commercial ice
machines, including which types of equipment, under which applications
the standard applies, and whether the listing of R-290 should apply to
commercial ice machines that have a remote compressor and are not self-
contained.

E. Industrial Process Refrigeration--Proposed Listing of HFC-32, HFO-
1234yf, HFO-1234ze(E), R-454A, R-454B, R-454C, R-455A, R-457A, and R-
516A as Acceptable, Subject to Use Conditions, for Use in New
Industrial Process Refrigeration

    EPA is proposing to list HFC-32, HFO-1234yf, HFO-1234ze(E), and the
refrigerant blends R-454A, R-454B, R-454C, R-455A, R-457A, and R-516A
as acceptable, subject to use conditions, for use in new industrial
process refrigeration.
    Most of the use conditions proposed for the proposed A2L
refrigerants when used in IPR are the same as those proposed for other
end-uses. Because of this similarity, EPA discusses the use conditions
that would apply to all five end-uses in section II.H. In summary, the
common use conditions proposed include the following: restricting the
use of each refrigerant to new equipment that is specifically designed
for that refrigerant; use consistent with the 2nd edition of UL 60335-
2-89, 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, technicians, and first responders of potential flammability
hazards.
    The following use condition also applies for R-32 and R-454B in
industrial process refrigeration: these substitutes may only be used in
chillers for IPR.
    The following use condition also applies for R-454A in IPR: this
substitute may only be used either in chillers for IPR, in equipment
with a refrigerant charge capacity less than 200 pounds, or in the high
temperature side of a cascade system.
    The regulatory text of the proposed decisions appears in tables at
the end of this document. If finalized as proposed, this text would be
codified in appendix Y to 40 CFR part 82, subpart G. The proposed
regulatory text contains listing decisions for the end-use discussed
above. EPA notes that there may be other legal obligations pertaining
to the manufacture, use, handling, and disposal of the proposed
refrigerants that are not included in the information listed in the
tables (e.g., the CAA section 608(c)(2) venting prohibition, or DOT
requirements for transport of flammable gases). Flammable refrigerants
being recovered or otherwise disposed of from IPR equipment are likely
to be hazardous waste under RCRA (see 40 CFR parts 260 through 270).
1. Background on Industrial Process Refrigeration
    IPR systems cool process streams in industrial applications, for
example, machining of metal products, fermentation of beer, or
operation of hydraulic circuits. The choice of substitute for specific
applications depends on ambient and required operating temperatures and
pressures. It is EPA's understanding that this type of equipment
generally falls under the scope of UL 60335-2-89, ``Requirements for
Commercial Refrigerating Appliances and Ice-Makers with an Incorporated
or Remote Refrigerant Unit or Motor-Compressor.'' In contrast,
industrial process air conditioning primarily cools people, may also
cool processes, and follows a different UL standard. In addition,
sometimes chillers are used primarily to cool process streams, rather
than for comfort cooling. EPA describes this application as ``chillers
in IPR.''
2. What are the ASHRAE classifications for refrigerant flammability?
    ASHRAE 34-2022 categorizes the refrigerants proposed for IPR in
this section as being in the A2L Safety Group. See section II.A.2 for
further discussion on ASHRAE classifications.
3. What are HFC-32, HFO-1234yf, HFO-1234ze(E), R-454A, R-454B, R-454C,
R-455A, R-457A, and R-516A and how do they compare to other
refrigerants in the same end-use?
    See section II.A.3 for further discussion on the environmental,
flammability, toxicity, and exposure information for these
refrigerants.

    The redacted submission and supporting documentation for HFC-32,
HFO-1234yf, HFO-1234ze(E), blends R-454A, R-454B, R-454C, R-455A, R-
457A, and R-516A is provided in the docket for this proposed rule (EPA-
HQ-OAR-2023-0043) at https://www.regulations.gov. EPA performed risk
screening assessments to examine the health and environmental risks of
these substitutes. These risk screens are available in the docket for
this proposed rule.48 49 50 51 52 53 54 55 56
---------------------------------------------------------------------------

    \48\ ICF, 2023r. Risk Screen on Substitutes in Industrial
Process Refrigeration (New Equipment); Substitute: HFC-32
(Difluoromethane).
    \49\ ICF, 2023s. Risk Screen on Substitutes in Industrial
Process Refrigeration, Cold Storage Warehouses, and Ice Skating
Rinks (New Equipment); Substitute: HFO-1234yf.
    \50\ ICF, 2023t. Risk Screen on Substitutes in Industrial
Process Refrigeration, Cold Storage Warehouses, and Ice Skating
Rinks (New Equipment); Substitute: HFO-1234ze(E) (Solstice[supreg]
ze, Solstice[supreg] 1234ze).
    \51\ ICF, 2023u. Risk Screen on Substitutes in Industrial
Process Refrigeration and Cold Storage Warehouses (New Equipment);
Substitute: R-454A (Opteon[supreg] XL40).
    \52\ ICF, 2023v. Risk Screen on Substitutes in Industrial
Process Refrigeration (New Equipment); Substitute: R-454B
(Opteon[supreg] XL41).
    \53\ ICF, 2023w. Risk Screen on Substitutes in Industrial
Process Refrigeration, Cold Storage Warehouses, and Ice Skating
Rinks (New Equipment); Substitute: R-454C (OpteonTM
XL20).
    \54\ ICF, 2023x. Risk Screen on Substitutes in Industrial
Process Refrigeration, Cold Storage Warehouses, and Ice Skating
Rinks (New Equipment); Substitute: R-455A (Solstice[supreg] L40X).
    \55\ ICF, 2023y. Risk Screen on Substitutes in Industrial
Process Refrigeration, Cold Storage Warehouses, and Ice Skating
Rinks (New Equipment); Substitute: R-457A.
    \56\ ICF, 2023z. Risk Screen on Substitutes in Industrial
Process Refrigeration, Cold Storage Warehouses, and Ice Skating
Rinks (New Equipment); Substitute: R-516A.
---------------------------------------------------------------------------

    Comparison to other substitutes in this end-use: HFC-32, HFO-
1234yf, HFO-1234ze(E), and blends R-454A, R-454B, R-454C, R-455A, R-
457A, and R-516A all have an ODP of zero, comparable to or lower than
some of the acceptable substitutes in new IPR equipment, such as HFC-
134a, R-410A, and R-513A with ODPs of zero and hydrochlorofluoroolefin
(HCFO)-1233zd(E) with an ODP less than 0.0004.\57\
---------------------------------------------------------------------------

    \57\ WMO, 2018.
---------------------------------------------------------------------------

    HFO-1234yf and HFO-1234ze(E) have GWPs less than four and less than
six, respectively, comparable to that of R-290 and ammonia with GWPs of
3 and zero. R-454A, R-454B, R-454C, R-455A, R-457A, and R-516A have
GWPs ranging from 140 to 470, higher than some of the acceptable
substitutes for new IPR equipment, including R-290 and ammonia, and
lower than those of other substitutes such as R-450A and R-513A with
GWPs of about 600 and 630. HFC-32 has a GWP of 675, which is higher
than some of the acceptable substitutes including R-290, R-450A, and R-
513A; however, the GWP of HFC-32 is lower than those of R-410A and R-
404A, with GWPs of approximately 2,090 to 3,920, which are refrigerant
that have typically been employed in chillers for IPR.
    Information regarding the toxicity of other available alternatives
is provided in the previous listing decisions for new IPR (https://www.epa.gov/snap/substitutes-industrial-process-refrigeration).
Toxicity risks of use, determined by the likelihood of exceeding the
exposure limits of HFC-32, HFO-1234yf, HFO-1234ze(E), R-454A, R-454B,
R-454C, R-455A, R-457A, and R-516A in this end-use, is evaluated in the
risk screens referenced above. The toxicity risks of using HFO-1234yf
and the refrigerant blends in IPR, and of using all nine refrigerants
in chillers for IPR, are comparable to or lower than toxicity risks of
other available substitutes in the same end-use. Toxicity risks of the
proposed refrigerants can be mitigated by use consistent with ASHRAE
15-2022 and other industry standards, recommendations in the
manufacturers' SDS, and other safety precautions common in the
refrigeration and AC industry.
    The flammability risks with HFC-32, HFO-1234yf, HFO-1234ze(E), R-
454A, R-454B, R-454C, R-455A, R-457A, and R-516A in the IPR end-use,
determined by the likelihood of exceeding their respective lower
flammability limits, are evaluated in the risk screens referenced in
this section above. While these refrigerants may pose greater
flammability risk than available substitutes in the new IPR end-use
that are non-flammable, this risk can be mitigated by use consistent
with ASHRAE 15-2022 and UL 60335-2-89, required by our proposed use
conditions, as well as recommendations in the manufacturers' SDS and
other safety precautions common in the refrigeration and AC industry.
We also note that other acceptable refrigerants in the IPR end-use have
higher flammability and are classified in the A3 Safety Group, such as
R-290, butane (R-600), and propylene (R-1270). EPA is proposing use
conditions to reduce the potential risk associated with the
flammability of the proposed alternatives so that they will not pose
significantly greater risk than other acceptable substitutes in the new
IPR end-use.
    In addition, the proposed substitutes have lower GWPs than most
other available alternatives for the same uses. The proposed
refrigerants may provide additional lower-GWP options for situations
where other refrigerants with lower GWPs are not viable, such as
situations where sparks or flame might occur such that HCs are not
suitable for use, or for systems with remote compressors or equipment
requiring larger charge sizes, where refrigerant leaks are more likely
to create greater flammability risk. Given the wide range of
applications for IPR, not all refrigerants listed as acceptable under
SNAP will be suitable for the range of equipment in the IPR end-use. To
provide additional options to ensure the availability of substitutes
for the full range of IPR equipment with lower GWP and, therefore,
lower overall risk to human health and the environment, EPA is
proposing the listings for HFO-1234yf, HFO-1234ze(E), R-454C, R-455A,
R-457A, and R-516A as acceptable, subject to use conditions, for use in
IPR.
    EPA is also proposing to list the refrigerants HFC-32 and R-454B
with a use condition restricting their use to chillers in IPR. These
refrigerants have higher GWPs than the other refrigerants EPA is
proposing to list as acceptable, subject to use conditions; lower GWPs
than many currently listed acceptable substitutes for IPR that are
commonly in use; and lower flammability than HC refrigerants currently
listed as acceptable in IPR. The Agency expects that these refrigerants
may provide additional, lower-GWP options for chillers for IPR, where
greater volumetric capacity and higher operating pressures may be
required to operate properly than for other types of IPR equipment
(e.g., direct expansion systems), to address applications where other
substitutes with lower GWPs may not be technically feasible.
    EPA is also proposing to list the refrigerant R-454A with a use
condition that this substitute may only be used either in chillers for
IPR, in equipment with a refrigerant charge capacity less than 200
pounds, or in the high temperature side of a cascade system. This
refrigerant may provide additional, lower-GWP options for chillers for
IPR, where greater volumetric capacity and higher operating pressures
may be required to operate properly than for other types of IPR
equipment. R-454A may also address the additional challenges for
finding lower GWP refrigerants with higher capacity for ice skating
rinks with moderate charge sizes and for cascade systems, EPA is
proposing to list R-454A as acceptable, subject to use conditions, for
use in new ice skating rinks with a charge size capacity less than 200
pounds or for use

in the high-temperature side of a cascade system.
4. Why is EPA proposing these specific use conditions?
    The use conditions identified in the proposed listings above for
all nine refrigerants are explained in section II.H.1 in greater
detail.
    EPA is proposing the use condition for HFC-32 and R-454B
restricting their use to chillers for IPR because these substitutes
have higher GWPs than many of the available substitutes in IPR (e.g.,
HCs, HFOs); however, because chillers may require greater volumetric
capacity than other types of IPR equipment (e.g., DX systems), EPA is
proposing to list these two additional refrigerants to provide
additional options and to address a broader range of equipment and
applications. EPA also is proposing a use condition for R-454A that
would allow its use in chillers for IPR, as well as other certain other
applications, as described below in this section. In addition, the
Agency previously listed HFC-32, R-454A, and R-454B as acceptable,
subject to use conditions, in centrifugal and positive displacement
chillers for comfort cooling in SNAP Rule 25. EPA is proposing to list
the same refrigerants the same way for the same type of equipment
(chillers) because of similar technical issues, such as volumetric
capacity and operating pressure, which restrict the technical viability
of alternatives for some applications.
    EPA is proposing to list R-454A as acceptable, subject to use
conditions, in IPR with a use condition that this substitute may only
be used in chillers for IPR, in equipment with a refrigerant charge
capacity less than 200 pounds or in the high-temperature side of a
cascade system. EPA is proposing to allow use of R-454A for use in
chillers for IPR for the same reasons as above for HFC-32 and R-454B.
The Agency is also proposing this use condition to allow use of R-454A
less broadly than for the refrigerants HFO-1234yf, HFO-1234ze(E), R-
454C, R-455A, R-457A, and R-516A because its GWP is higher than those
other proposed listings for non-chiller IPR equipment (that has a GWP
of about 240, compared to less than four to 150). EPA's understanding
is that, in addition to the technical constraints for refrigerant in
chillers, there are two more situations where use of refrigerants is
likely to be more constrained, and thus, additional refrigerant options
may be helpful. The first of those situations is in what industry
standard ASHRAE 15-2022 identifies as a refrigerating system having a
``high probability'' that leaked refrigerant from a failed connection,
seal, or component could enter an occupied area. An example of such a
constraint is that ASHRAE 15-2022 and UL 60335-2-89 effectively set
charge limits for A2L refrigerants to less than 200 pounds for
applications inside an occupied space where people might be located. In
contrast, larger charge sizes could be used in ``low-probability''
locations where the general public is unlikely to come in contact with
the refrigerant, such as systems used outdoors or in a machinery room
with access restricted to facility employees. Where the general public
is unlikely to come into contact with any leaked refrigerant, such as
where charge sizes of 200 pounds or more of A2L refrigerant would be
allowed under the use conditions incorporating UL 60335-2-89 and ASHRAE
15-2022, there would be fewer space constraints and greater flexibility
in equipment design, so refrigeration system designers can accommodate
a narrower set of substitutes. Conversely, where people are more likely
to come into contact with any leaked refrigerant in an interior space,
refrigerant charge capacities of a system would be less than 200
pounds; there would be more space constraints, less flexibility in
equipment design, and potentially stricter code requirements, leading
to a need for more refrigerant options. Allowing the additional option
of R-424A for non-chiller IPR equipment with smaller refrigerant
charges would enable the use of a wider set of available substitutes to
manage safety (in particular, flammability and toxicity), as well as
allowing more options to achieve adequate performance where there may
be more constraints. Therefore, EPA is proposing to list R-454A as
acceptable, subject to use conditions, only for non-chiller IPR
equipment with a refrigerant charge capacity less than 200 pounds.
    EPA is also proposing to list R-454A as acceptable, subject to use
conditions, for use in the high temperature side of cascade systems
used for non-chiller IPR equipment. As discussed above in section
II.A.1, ``Background on retail food refrigeration,'' each system of a
cascade system uses a different refrigerant that is most suitable for
the given temperature range. Higher temperature systems, or the ``high
temperature side,'' have typically used HFCs as a refrigerant; however,
it is technologically achievable and has become more common to use
ammonia in the high temperature side. For lower temperature systems, or
the ``low temperature side'' of the cascade system, low boiling
refrigerants such as R-744 can be used. Considerations for the choice
of refrigerant on the high or low temperature side of cascade systems
are influenced by many factors including, but not limited to, a
refrigerant's toxicity and flammability, its temperature glide, and its
suitability to lower temperature applications. EPA understands that use
of flammable or toxic refrigerants, such as ammonia, on the high
temperature side of a cascade may be limited in certain circumstances
(e.g., based on building codes and/or standards). EPA notes that there
are a number of substitutes available for the low temperature side of
the cascade system with GWPs lower than that of R-454A. Therefore,
instead of proposing to list R-454A as acceptable, subject to narrowed
use limits and subject to use conditions, EPA is proposing to list R-
454A as acceptable, subject to use conditions, when it is used in the
high temperature side of cascade systems; this would expand the
refrigerant options that can comply with local building codes and
industry safety standards while meeting the more challenging
application of the high temperature side of a cascade system.
5. What additional information is EPA including in these proposed
listings?
    EPA is providing additional information related to these proposed
listings. 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.H.2 for
further discussion on what additional information EPA is including in
these proposed listings. 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.
6. On which topics is EPA specifically requesting comment?
    EPA is requesting comment on all aspects of the proposed decision
to list HFC-32, HFO-1234yf, HFO-1234ze(E), and the refrigerant blends
R-454A, R-454B, R-454C, R-455A, R-457A, and R-516A acceptable, subject
to use conditions, in IPR as discussed in this section II.E. EPA seeks
comment on the risk mitigation offered by the proposed use conditions,
including requiring compliance with the 2nd edition of UL 60335-2-89,
except to the extent the proposed rule conflicts with the UL standard,
in which case we propose that the conditions specified in the rule
would apply. We also request comment

on whether other use conditions would offer needed risk mitigation for
the flammable refrigerants proposed. EPA requests comment on whether
types of IPR equipment have been designed for the refrigerants
proposed; any information on the safety of such equipment in other
countries; and if and how such experience would translate to safe use
in the United States. The Agency requests comment on whether HFC-32, R-
454A, and R-454B should be listed as acceptable for chillers in IPR
given their higher GWP than some other alternatives listed as
acceptable, if they should not be listed in IPR at all, or if they
should be listed as acceptable for all types of IPR equipment, and if
so, why. Depending on public comments and information received, EPA may
revise the substitutes listed with a use condition for use only in
chillers for IPR or may not finalize some of the proposed listings.

F. Cold Storage Warehouses--Proposed Listing of HFO-1234yf, HFO-
1234ze(E), R-454A, R-454C, R-455A, R-457A and R-516A as Acceptable,
Subject to Use Conditions, for Use in New Cold Storage Warehouses

    EPA is proposing to list HFO-1234yf, HFO-1234ze(E), and the
refrigerant blends R-454A, R-454C, R-455A, R-457A, and R-516A as
acceptable, subject to use conditions, for use in new cold storage
warehouses.
    Several use conditions proposed for cold storage warehouses are
common to those proposed for the other end-uses in this rule. Because
of this similarity, EPA discusses the use conditions that would apply
to all five end-uses in section II.H. In summary, the common use
conditions proposed include the following: restricting the use of each
refrigerant to new equipment that is specifically designed for that
refrigerant; use consistent with the 2nd edition of UL 60335-2-89,
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, technicians, and
first responders of potential flammability hazards.
    The following proposed use condition would also apply to R-454A in
cold storage warehouses: this substitute may only be used either in
equipment with a refrigerant charge capacity less than 200 pounds or in
the high temperature side of a cascade system.
    The regulatory text of the proposed decisions appears in tables at
the end of this document. If finalized as proposed, this text would be
codified in appendix Y to 40 CFR part 82, subpart G. The proposed
regulatory text contains listing decisions for the end-use discussed
above. EPA notes that there may be other legal obligations pertaining
to the manufacture, use, handling, and disposal of the proposed
refrigerants that are not included in the information listed in the
tables (e.g., the CAA section 608(c)(2) venting prohibition, or
Department of Transportation requirements for transport of flammable
gases). Flammable refrigerants being recovered or otherwise disposed of
from cold storage warehouses are likely to be hazardous waste under
RCRA (see 40 CFR parts 260 through 270).
1. Background on Cold Storage Warehouses
    Cold storage warehouses, an end-use within the SNAP program, are
refrigerated warehousing and are used to preserve meat, produce, dairy
products, and other perishable goods prior to their distribution and
sale.
    Refrigerant choices depend on the refrigerant charge, ambient
temperatures and the temperature required, system performance, energy
efficiency, and health, safety and environmental considerations, among
other things. The majority of cold storage warehouses in the United
States use ammonia as the refrigerant in a vapor compression cycle,
although some rely on other refrigerants. In addition to regulations
pursuant to the SNAP program, other federal or local regulations may
also affect refrigerant choice. For instance, regulations from OSHA may
restrict or place requirements on the use of some refrigerants, such as
ammonia (R-717). Building codes from local and state agencies may also
incorporate limits on the charge size of particular refrigerants. EPA
understands that this type of equipment falls under the scope of UL
60335-2-89, ``Household and Similar Electrical Appliances--Safety--Part
2-89: Requirements for Commercial Refrigerating Appliances and Ice-
Makers with an Incorporated or Remote Refrigerant Unit or Motor-
Compressor.''
    EPA is proposing to list HFO-1234yf, HFO-1234ze(E), R-454A, R-454C,
R-455A, R-457A, and R-516A as acceptable, subject to use conditions, in
new cold storage warehouses.
2. What are the ASHRAE classifications for refrigerant flammability?
    ASHRAE 34-2022 categorizes the refrigerants proposed for cold
storage warehouses in this section as being in the A2L Safety Group.
See section II.A.2 for further discussion on ASHRAE classifications of
these refrigerants.
3. What are HFO-1234yf, HFO-1234ze(E), R-454A, R-454C, R-455A, R-457A,
and R-516A and how do they compare to other refrigerants in the same
end-use?
    See section II.A.3 for further discussion on the environmental,
flammability, toxicity, and exposure information for HFO-1234yf, HFO-
1234ze(E), R-454A, R-454C, R-455A, R-457A, and R-516A.\58\
---------------------------------------------------------------------------

    \58\ EPA previously listed HFO-1234yf as acceptable, subject to
use conditions, in motor vehicle AC in light-duty vehicles (74 FR
53445, October 19, 2009), in heavy-duty pickup trucks and complete
heavy-duty vans (81 FR 86778, December 1, 2016) and in nonroad
vehicles and service fittings for small refrigerant cans (87 FR
26276, May 4, 2022). EPA previously listed R-454A, R-454C, and R-
457A as acceptable subject to use conditions as substitutes in
residential and light commercial AC and HPs (86 FR 24444, May 6,
2021).
---------------------------------------------------------------------------

    Redacted submissions and supporting documentation for HFO-1234yf,
HFO-1234ze(E), and the refrigerant blends are provided in the docket
for this proposed rule (EPA-HQ-OAR-2023-0043) at https://www.regulations.gov. EPA performed risk screening assessments to
examine the health and environmental risks of each of these
substitutes. These risk screens are available in the docket for this
proposed rule.59 60 61 62 63 64 65
---------------------------------------------------------------------------

    \59\ ICF, 2023s. Op. cit.
    \60\ ICF, 2023t. Op. cit.
    \61\ ICF, 2023u. Op. cit.
    \62\ ICF, 2023w. Op. cit.
    \63\ ICF, 2023x. Op. cit.
    \64\ ICF, 2023y. Op. cit.
    \65\ ICF, 2023z. Op. cit.
---------------------------------------------------------------------------

    Comparison to other substitutes in this end-use: HFO-1234yf, HFO-
1234ze(E), and R-454A, R-454C, R-455A, R-457A, and R-516A all have an
ODP of zero, comparable to or lower than some of the acceptable
substitutes in this end-use, such as ammonia with an ODP of zero and
HCFO-1233zd(E) with an ODP less than 0.0004.
    HFO-1234yf and HFO-1234ze(E) have GWPs less than four and less than
six, respectively, comparable to that of (HCFO)-1233zd(E),
CO2, and ammonia with GWPs of 3.7, one, and zero
respectively. R-454A, R-454C, R-455A, R-457A, and R-516A have GWPs
ranging from 140 to 270, higher than some of the acceptable substitutes
for new cold storage warehouses, including HCFO-1233zd(E),
CO2, and ammonia with GWPs of 3.7, one, and zero,
respectively, and lower than those of other acceptable substitutes such
as R-450A, R-513A, and R-407F with GWPs of about 600, 630, and 1,820,
respectively.
    Information regarding the toxicity of other available alternatives
is provided in the listing decisions previously made (see https://
www.epa.gov/snap/

substitutes-cold-storage-warehouses). Toxicity risks of use, determined
by the likelihood of exceeding the exposure limit of HFO-1234yf, HFO-
1234ze(E), and the refrigerant blends in these end-uses, are evaluated
in the risk screens referenced above. The toxicity risks of using HFO-
1234yf, HFO-1234ze(E), and the refrigerant blends in commercial
refrigeration are comparable to or lower than toxicity risks of other
available substitutes in the same end-use. Toxicity risks of the
proposed refrigerants can be minimized by use consistent with ASHRAE
15-2022 and other industry standards, recommendations in the
manufacturers' SDS, and other safety precautions common in the
refrigeration and AC industry.
    The flammability risks with HFO-1234yf, HFO-1234ze(E), R-454A, R-
454C, R-455A, R-457A, and R-516A in this end-use, determined by the
likelihood of exceeding their respective lower flammability limits, are
evaluated in the risk screens referenced above. In conclusion, while
these refrigerants may pose greater flammability risk than other
available, non-flammable substitutes in the same end-use, this risk can
be minimized by use consistent with ASHRAE 15-2022 and other industry
standards such as UL 60335-2-89--which is required by our proposed use
conditions--as well as recommendations in the manufacturers' SDS and
other safety precautions common in the refrigeration and AC industry.
EPA is proposing use conditions to reduce the potential risk associated
with the flammability of these alternatives so that they will not pose
significantly greater risk than other acceptable substitutes in this
end-use.
    The proposed refrigerants provide additional lower-GWP options for
situations where other refrigerants with lower GWPs are not viable,
such as for use of ammonia in systems with remote compressors or in
locations where local regulations restrict its use, or where a lower
pressure refrigerant like HCFO-1233zd(E) is not technically viable. Not
all refrigerants listed as acceptable under SNAP will be suitable for
the range of equipment in the cold storage warehouse end-use. To
provide additional options to ensure the availability of substitutes
for the full range of cold storage warehouses with lower GWP and,
therefore, lower overall risk to human health and the environment, EPA
is proposing the listings for HFO-1234yf, HFO-1234ze(E), R-454C, R-
455A, R-457A, and R-516A as acceptable, subject to use conditions, for
use in all types of cold storage warehouses. In addition, to account
for the additional challenges for finding lower GWP refrigerants for
cold storage warehouses with moderate charge sizes and for cascade
systems, EPA is proposing to list R-454A as acceptable, subject to use
conditions, for use in cold storage warehouses with a charge size
capacity less than 200 pounds or for use in the high-temperature side
of a cascade system.
4. Why is EPA proposing these specific use conditions?
    The proposed use conditions identified in the proposed listings
above are explained in section II.H.1.
    This proposal applies to end-uses covered by UL 60335-2-89,
including the SNAP cold storage warehouses end-use. In addition, ASHRAE
15-2022 applies to these refrigeration systems.
    The standard UL 60335-2-89 discussed in section II.H indicates that
refrigerant charges greater than a specific amount (called
``m3'' in the standard and based on the refrigerant's LFL)
are beyond its scope and that national standards might apply, such as
ASHRAE 15-2022. Hence, EPA is proposing to require adherence to both
standards as use conditions for cold storage warehouses, broadening the
coverage under this proposed rule.
    EPA is proposing to incorporate by reference ASHRAE 15-2022,
including all addenda published by the date of this proposal, in use
conditions that apply to use of the proposed A2L refrigerants in new
cold storage warehouses. Where the requirements specified in this
proposed rule (if finalized) and ASHRAE 15-2022 differ, the
requirements of this rule would apply.
    EPA recognizes that ASHRAE 15-2022 is undergoing continuous
maintenance with publication of periodic addenda and is typically
updated and republished every three years. While this proposed rule
incorporates all addenda to ASHRAE 15-2022 published by the date of
this proposal, there may be additional changes by the time EPA issues a
final rule based upon this proposal. However, given EPA would not have
reviewed and proposed use conditions based on those changes, EPA is not
proposing to include addenda or other changes made to ASHRAE 15-2022
after the date of the proposed rule.
    EPA is proposing to list R-454A as acceptable, subject to use
conditions, in cold storage warehouses with a use condition that this
substitute may only be used either in equipment with a refrigerant
charge capacity less than 200 pounds or in the high-temperature side of
a cascade system. The Agency is proposing this use condition to allow
use of R-454A less broadly than for the other refrigerants proposed for
use in cold storage warehouses because its GWP is higher than those of
the other proposed listings for this end-use (about 240, compared to
less than four to 150). EPA's understanding is that there are two
particular situations where use of refrigerants could be more
constrained, and thus, additional refrigerant options may be helpful.
The first of those situations is in what the industry standard ASHRAE
15-2022 identifies as a refrigerating system having a ``high
probability'' that leaked refrigerant from a failed connection, seal,
or component could enter an occupied area. An example of such a
constraint is that ASHRAE 15-2022 and UL 60335-2-89 effectively set
charge limits for A2L refrigerants to less than 200 pounds for
applications inside occupied areas. In contrast, larger charge sizes
could be used in ``low-probability'' locations where people are
unlikely to come in contact with the refrigerant, such as systems used
outdoors or in a machinery room with access restricted to employees.
Where people are unlikely to come into contact with any leaked
refrigerant, such as where charge sizes of 200 pounds or more of A2L
refrigerant would be allowed under the use conditions incorporating UL
60335-2-89 and ASHRAE 15-2022, there would be fewer space constraints
and greater flexibility in equipment design, so refrigeration system
designers can accommodate a narrower set of substitutes. Conversely,
where people are more likely to come into contact with any leaked
refrigerant in an interior space, refrigerant charge capacities of a
system would be less than 200 pounds; there would be more space
constraints, less flexibility in equipment design, and potentially
stricter code requirements, leading to a need for more refrigerant
options. Allowing the additional option of R-454A for cold storage
warehouses with smaller refrigerant charges would enable the use of a
wider set of available substitutes to manage safety (in particular,
flammability and toxicity), as well as allowing more options to achieve
adequate performance where there may be more constraints. Therefore,
EPA is proposing to list R-454A as acceptable, subject to use
conditions, only for cold storage warehouses with a refrigerant charge
capacity less than 200 pounds.
    EPA is also proposing to list R-454A as acceptable, subject to use
conditions, for use in the high temperature side of cascade systems
used for cold storage

warehouses. As discussed above in section II.A.1, ``Background on
retail food refrigeration,'' each system of a cascade system uses a
different refrigerant that is most suitable for the given temperature
range. Higher temperature systems, or the ``high temperature side,''
have typically used HFCs as a refrigerant; however, it is
technologically achievable and has become more common to use ammonia in
the high temperature side. For lower temperature systems, or the ``low
temperature side'' of the cascade system, low boiling refrigerants such
as R-744 can be used. Considerations for the choice of refrigerant on
the high or low temperature side of cascade systems are influenced by
many factors including, but not limited to, a refrigerant's toxicity
and flammability, its temperature glide, and its suitability to lower
temperature applications. EPA understands that use of flammable or
toxic refrigerants, such as ammonia, on the high temperature side of a
cascade may be limited in certain circumstances (e.g., based on
building codes and/or standards). EPA notes that there are a number of
substitutes available for the low temperature side of the cascade
system with GWPs lower than that of R-454A. Therefore, instead of
proposing to list R-454A as acceptable, subject to narrowed use limits
and subject to use conditions, EPA is proposing to list R-454A as
acceptable, subject to use conditions, when it is used in the high
temperature side of cascade systems; this would expand the refrigerant
options that can comply with local building codes and industry safety
standards while meeting the more challenging application of the high
temperature side of a cascade system.
5. What additional information is EPA including in these proposed
listings?
    EPA is providing additional information related to these proposed
listings. 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.H.2 for
further discussion on what additional information EPA is including in
these proposed listings. 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.
6. On which topics is EPA specifically requesting comment?
    EPA is requesting comment on all aspects of the proposed decision
to list HFO-1234yf, HFO-1234ze(E), R-454A, R-454C, R-455A, R-457A, and
R-516A acceptable, subject to use conditions, in new cold storage
warehouses as discussed in this section II.F. EPA seeks comment on the
risk mitigation offered by the proposed use conditions, including
requiring compliance with the 2nd edition of UL 60335-2-89 under the
SNAP program, except to the extent the proposed rule conflicts with the
UL Standard, in which case we propose that the use conditions specified
in the rule would apply. The Agency takes comment on our proposal to
limit R-454A to use either in equipment with a refrigerant charge
capacity less than 200 pounds or in the high temperature side of a
cascade system. We also request comment on whether EPA should consider
other use conditions to further mitigate potential risk from
refrigerants. EPA requests comment on whether cold storage warehouses
have been designed for or manufactured with the refrigerants proposed
and any information on the safety of such equipment in other countries,
and if and how such experience would translate to safe use in the
United States.

G. Ice Skating Rinks--Proposed Listing of HFO-1234yf, HFO-1234ze(E), R-
454C, R-455A, R-457A, and R-516A as Acceptable, Subject to Use
Conditions, for Use in New Ice Skating Rinks With a Remote Compressor

    EPA is proposing to list HFO-1234yf, HFO-1234ze(E), and the
refrigerant blends R-454C, R-455A, R-457A, and R-516A as acceptable,
subject to use conditions, for use in new ice skating rinks.
    Several use conditions proposed for ice skating rinks with a remote
compressor are common to those proposed for other end-uses. Because of
this similarity, EPA discusses the use conditions that would apply to
all five end-uses in section II.H. For ice skating rinks with remote
compressors, those are the only use conditions EPA is proposing. In
summary, the common use conditions proposed include the following:
restricting the use of each refrigerant to new equipment that is
specifically designed for that refrigerant; use consistent with the 2nd
edition of UL 60335-2-89, 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, technicians, and first responders of potential flammability
hazards.
    The regulatory text of the proposed decisions appears in tables at
the end of this document. If finalized as proposed, this text would be
codified in appendix Y to 40 CFR part 82, subpart G. EPA notes that
there may be other legal obligations pertaining to the manufacture,
use, handling, and disposal of the proposed refrigerants that are not
included in the information listed in the tables (e.g., the CAA section
608(c)(2) venting prohibition, or DOT requirements for transport of
flammable gases). Flammable refrigerants being recovered or otherwise
disposed of from ice skating rinks are likely to be hazardous waste
under RCRA (see 40 CFR parts 260 through 270).
1. Background on Ice Skating Rinks
    Ice skating rinks, an end-use within the SNAP program, are used by
the general public for recreational purposes and also include
professional rinks. These systems frequently use secondary loop
refrigeration systems, where a primary loop containing a refrigerant
uses a remote compressor that is in a location away from the public,
such as a machinery room, and a secondary loop, containing propylene
glycol, water, or another innocuous fluid, is used to directly cool the
ice. Other types of refrigeration systems for ice skating rinks use a
direct heat exchange system, where the refrigerant moves directly under
the rink. The proposed listings would apply only to ice skating rinks
that have a remote compressor.
    Refrigerant choice depends on the refrigerant charge; ambient
temperatures and the temperature required; system performance; energy
efficiency; and health, safety, and environmental considerations, among
other things. In addition to regulations pursuant to the SNAP program,
other federal or local regulations may also affect refrigerant choice.
For instance, regulations from OSHA may restrict or place requirements
on the use of some refrigerants, such as ammonia (R-717). Building
codes from local and state agencies may also incorporate limits on the
amount of particular refrigerants used. Acceptable substitutes in use
today for new ice skating rinks include ammonia, CO2, HCFO-
1233zd(E) as well as HFCs and HFC/HFO blends. These can be used alone
or in combination with other refrigerants in other parts of the
equipment, depending on the equipment and its design (e.g., a secondary
loop contains one refrigerant while the primary loop contains a
different refrigerant). This type of equipment falls under the scope of
UL 60335-2-89, ``Requirements for Commercial Refrigerating Appliances
and Ice-Makers with an Incorporated or

Remote Refrigerant Unit or Motor-Compressor.''
2. What are the ASHRAE classifications for refrigerant flammability?
    ASHRAE Standard 34-2022 categorizes the refrigerants proposed for
ice skating rinks in this section as being in the A2L Safety Group. See
section II.A.2 for further discussion on ASHRAE classifications of
these refrigerants.
3. What are HFO-1234yf, HFO-1234ze(E), R-454C, R-455A, R-457A, and R-
516A and how do they compare to other refrigerants in the same end-use?
    See section II.A.3 for further discussion on the environmental,
flammability, toxicity, and exposure information for these
refrigerants.\66\
---------------------------------------------------------------------------

    \66\ EPA previously listed HFO-1234yf as acceptable, subject to
use conditions, in motor vehicle AC in light-duty vehicles (74 FR
53445, October 19, 2009), in heavy-duty pickup trucks and complete
heavy-duty vans (81 FR 86778, December 1, 2016) and in nonroad
vehicles and service fittings for small refrigerant cans (87 FR
26276, May 4, 2022). EPA previously listed R-454C, and R-457A as
acceptable, subject to use conditions, as substitutes in residential
and light commercial AC and HPs (86 FR 24444, May 6, 2021).
---------------------------------------------------------------------------

    Redacted submissions and supporting documentation for HFO-1234yf,
HFO-1234ze(E) and the blends R-454C, R-455A, R-457A and R-516A are
provided in the docket for this proposed rule (EPA-HQ-OAR-2023-0043) at
https://www.regulations.gov. EPA performed a risk screening assessment
to examine the health and environmental risks of each of these
substitutes. These risk screens are available in the docket for this
proposed rule.67 68 69 70 71 72
---------------------------------------------------------------------------

    \67\ ICF, 2023s. Op. cit.
    \68\ ICF, 2023t. Op. cit.
    \69\ ICF, 2023w. Op. cit.
    \70\ ICF, 2023x. Op. cit.
    \71\ ICF, 2023y. Op. cit.
    \72\ ICF, 2023z. Op. cit.
---------------------------------------------------------------------------

    Comparison to other substitutes in this end-use: HFO-1234yf, HFO-
1234ze(E) and R-454C, R-455A, R-457A, and R-516A all have an ODP of
zero, comparable to or lower than some of the acceptable substitutes in
this end-use, such as ammonia with an ODP of zero and HCFO-1233zd(E)
with an ODP of less than 0.0004.
    HFO-1234yf and HFO-1234ze(E) have GWPs of less than four and less
than six, respectively, comparable to or lower than that of other
acceptable substitutes for new ice skating rinks, such as ammonia,
CO2, and HCFO-1233zd(E) with GWPs of zero, one, and 3.7,
respectively.
    R-454C, R-455A, R-457A, and R-516A have GWPs, ranging from about
140 to 150, which are higher than that of other acceptable substitutes
for ice skating rinks, including ammonia, CO2, and HCFO-
1233zd(E) with GWPs of zero, one, and 3.7, respectively. The GWPs of
HFO-1234yf, HFO-1234ze(E), R-454C, R-455A, R-457A, and R-516A are lower
than some of the acceptable substitutes for new ice skating rinks, such
as R-450A, R-449A, and R-507A with GWPs of approximately 600, 1,400,
and 3,990, respectively.
    Information regarding the toxicity of other available alternatives
is provided in the listing decisions previously made (see https://www.epa.gov/snap/substitutes-ice-skating-rinks). Toxicity risks of use,
determined by the likelihood of exceeding the exposure limit of HFO-
1234yf, HFO-1234ze(E), R-454C, R-455A, R-457A, and R-516A in these end-
uses, are evaluated in the risk screens referenced above. The toxicity
risks of using HFO-1234yf, HFO-1234ze(E), and R-454C, R-455A, R-457A
and R-516A in ice skating rinks with remote compressors are comparable
to or lower than toxicity risks of other available substitutes in the
same end-use. Toxicity risks of the proposed refrigerants can be
minimized by use consistent with ASHRAE 15-2022--which would be
required by our proposed use conditions--and other industry standards,
recommendations in the manufacturers' SDS, and other safety precautions
common in the refrigeration and AC industry.
    The potential flammability risks of HFO-1234yf, HFO-1234ze(E) R-
454C, R-455A, R-457A, and R-516A in this end-use, determined by the
likelihood of exceeding their respective lower flammability limits, are
evaluated in the risk screens referenced above. In conclusion, while
these refrigerants may pose greater flammability risk than other
available substitutes in the same end-use, this risk can be minimized
by use consistent with ASHRAE 15-2022 and other industry standards such
as UL 60335-2-89--which is required by our proposed use conditions--as
well as recommendations in the manufacturers' SDS and other safety
precautions common in the refrigeration and AC industry. EPA is
proposing use conditions to reduce the potential risk associated with
the flammability of these alternatives so that they will not pose
significantly greater risk than other acceptable substitutes in this
end-use. In addition, EPA is proposing to limit these listings to
equipment with a remote compressor. Such equipment reduces the chances
of exposure to the general public compared to refrigerants that are
piped directly under an ice skating rink. This also can reduce the
amount of refrigerant used, potentially reducing climate impacts of any
refrigerant released.
    In addition, the proposed substitutes have lower GWPs than most
other available alternatives for the same end-use. The proposed
refrigerants may provide additional lower-GWP options for situations
where other refrigerants with lower GWPs are not viable, such as in
locations where local regulations restrict use of ammonia. Not all
refrigerants listed as acceptable under SNAP will be suitable for the
range of equipment in the ice skating rinks end-use. To provide
additional options to ensure the availability of substitutes with lower
GWP for more ice skating rinks and, therefore, lower overall risk to
human health and the environment, EPA is proposing the listings for
HFO-1234yf, HFO-1234ze(E), R-454C, R-455A, R-457A, and R-516A as
acceptable, subject to use conditions, for use in new ice skating
rinks.
4. Why is EPA proposing these specific use conditions?
    The use conditions identified in the proposed listings above are
explained in section II.H.1.
    This proposal applies to end-uses covered by UL 60335-2-89,
including the SNAP ice skating rinks end-use. In addition, ASHRAE 15-
2022 applies to these refrigeration systems.
    The standard UL 60335-2-89 discussed in section II.H indicates that
refrigerant charges greater than a specific amount (called
``m3'' in the standard and based on the refrigerant's LFL)
are beyond its scope and that national standards might apply, such as
ASHRAE 15-2022. Hence, EPA is proposing to require adherence to both
standards as use conditions for ice skating rinks, broadening the
coverage under this proposed rule.
    EPA is proposing to incorporate by reference ASHRAE 15-2022,
including all addenda published by the date of this proposal, in use
conditions that apply to use of the proposed A2L refrigerants in new
ice skating rinks. Where the requirements specified in this proposed
rule (if finalized) and ASHRAE 15-2022 differ, the requirements of this
rule would apply.
    EPA recognizes that ASHRAE 15-2022 is undergoing continuous
maintenance with publication of periodic addenda and is typically
updated and republished every three years. While this proposed rule
incorporates all addenda to ASHRAE 15-2022 published by the date of
this proposal, there may be additional changes by the time EPA issues a
final rule based upon this proposal. However, given EPA would not have
reviewed

and proposed use conditions based on those changes, EPA is not
proposing to include addenda or other changes made to ASHRAE 15-2022
after the date of the proposed rule.
    EPA is proposing a use condition that the six A2L refrigerants may
only be used in new equipment that includes a remote compressor. This
is intended to ensure that these flammable refrigerants, which are
likely to use large charge sizes, are only used in situations where the
refrigerant is removed from the presence of ice skaters and other
members of the general public. This would reduce the likelihood of
exposure or leaks of the refrigerant near the general public and
instead allow facility employees and trained technicians to control
access to the refrigerant.
5. What additional information is EPA including in these proposed
listings?
    EPA is providing additional information related to these proposed
listings. 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.H.2 for
further discussion on what additional information EPA is including in
these proposed listings. 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.
6. On which topics is EPA specifically requesting comment?
    EPA is requesting comment on all aspects of this proposed decision
to list HFO-1234yf, HFO-1234ze(E), R-454C, R-455A, R-457A, and R-516A
as acceptable, subject to use conditions, in new ice skating rinks with
a remote compressor as discussed in this section II.G. We request
comment on our initial evaluation and our proposal to find HFO-1234yf,
HFO-1234ze(E), R-454C, R-455A, R-457A, and R-516A acceptable, subject
to use conditions, for use in new ice skating rinks. EPA seeks comment
on the risk mitigation offered by the proposed use conditions,
including requiring compliance with the 2nd edition of UL 60335-2-89,
except to the extent the proposed rule conflicts with the UL Standard,
in which case we propose that the use conditions specified in the rule
would apply. We also request comment on whether EPA should consider
other use conditions to further mitigate potential risk from
refrigerants. EPA requests comment on whether equipment for such ice
skating rinks with remote compressors in the United States has already
been designed or manufactured for the refrigerants proposed and any
information on the safety of such equipment in other countries, and if
and how such experience would translate to safe use in the United
States. The Agency also requests comment on whether these listings
should be restricted to ice skating rinks with a remote compressor, if
they should be allowed for any ice skating rink, or if they should be
limited to a different subset of ice skating rinks (e.g., for use only
in the primary loop of a secondary loop systems).

H. Use Conditions and Further Information for Retail Food
Refrigeration, Commercial Ice Machines, Industrial Process
Refrigeration, Cold Storage Warehouses, and Ice Skating Rinks With a
Remote Compressor

1. What use conditions is EPA proposing and why?
    As described above, EPA is proposing to list:
     HFO-1234yf, HFO-1234ze(E), R-454C, R-455A, R-457A, and R-
516A as acceptable, subject to use conditions, for use in new equipment
in stand-alone units, remote condensing units, supermarket systems, and
refrigerated food processing and dispensing equipment;
     R-454A as acceptable, subject to use conditions, for use
in new equipment in remote condensing units and supermarket systems;
     R-290 as acceptable, subject to use conditions, for use in
new refrigerated food processing and dispensing equipment;
     HFC-32, HFO-1234yf, R-454A, R-454B, R-454C, R-455A, R-
457A, and R-516A as acceptable, subject to use conditions, for use in
new commercial ice machines;
     HFO-1234yf, HFO-1234ze(E), R-454A, R-454C, R-455A, R-457A,
and R-516A as acceptable, subject to use conditions, for used in new
IPR equipment and HFC-32 and R-454B, for use in new chillers for IPR;
     HFO-1234yf, HFO-1234ze(E), R-454A, R-454C, R-455A, R-457A,
and R-516A as acceptable, subject to use conditions, for use in new
cold storage warehouses; and
     HFO-1234yf, HFO-1234ze(E), R-454C, R-455A, R-457A, and R-
516A as acceptable, subject to use conditions, for use in new ice
skating rinks with remote compressors.
    In addition, EPA is proposing to update the use conditions that
apply to the existing listings of:
     R-290 as acceptable, subject to use conditions, for use in
new retail food refrigeration stand-alone units; and
     R-290 as acceptable, subject to use conditions, for use in
new self-contained commercial ice machines.
    These use conditions are summarized in the listings under preamble
units II.A, II.C, II.E, II.F, and II.G, and the revisions to the use
conditions are summarized under preamble units II.B and II.D and are
explained here in greater detail. The proposed use conditions (either
as new listings or revisions to an existing listing) include
restricting the use of each refrigerant to new equipment that is
specifically designed for the refrigerant; use consistent with the 2nd
edition of UL 60335-2-89, 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, technicians, and first responders of potential flammability
hazards. The specific use conditions are intended to allow for the use
of these flammable 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 proposing 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. EPA is
unaware of information on how to address hazards if these flammable
refrigerants were to be used in equipment that was designed for non-
flammable refrigerants. Given the flammable nature of these
refrigerants, the fact that EPA is unaware of information to assess the
risk if such retrofits were allowed, and because the refrigerants were
not submitted to the SNAP program for retrofits, EPA has not reviewed
them for retrofit applications for this proposal and is only proposing
that they may be used in new equipment which can be properly designed
for their use. This proposed 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
    To ensure safe use of the proposed flammable refrigerants, EPA is

proposing to incorporate by reference certain industry consensus safety
standards in a use condition. Specifically, the Agency is proposing
that the flammable refrigerants may be used only in equipment that
meets all requirements in the 2nd edition of UL 60335-2-89.
    Currently, new stand-alone units using R-290 are subject to a use
condition to meet the requirements of Appendix SB of the 10th edition
of the standard UL 471. If this rule becomes final as proposed, stand-
alone units using R-290 manufactured before the effective date could
continue to be used under SNAP and would remain in compliance with the
SNAP use conditions as long as they met the applicable use conditions
when they were manufactured. EPA is proposing that new stand-alone
units using R-290 manufactured from the effective date of the final
rule through September 29, 2024, must meet the requirements of either
Appendix SB of the 10th edition of UL 471 or the 2nd edition of UL
60335-2-89. The Agency is also proposing that new stand-alone units
using R-290 that are manufactured on or after September 30, 2024, must
meet the requirements of the 2nd edition of UL 60335-2-89, rather than
the earlier UL standards.
    Currently, new self-contained commercial ice machines using R-290
must meet the requirements of Appendix SA of the 8th edition of UL 563.
If this rule becomes final as proposed, commercial ice machines using
R-290 manufactured before the effective date of a final rule could
continue to be used under SNAP and would remain in compliance with the
SNAP use conditions as long as they met the applicable use conditions
when they were manufactured. EPA is proposing that new self-contained
commercial ice machines using R-290 that are manufactured from the
effective date of the final rule through September 29, 2024, must meet
the requirements of either Appendix SA of the 8th edition of UL 563 or
the 2nd edition of UL 60335-2-89. The Agency is also proposing that new
self-contained commercial ice machines using R-290 that are
manufactured on or after September 30, 2024, must meet the requirements
of the 2nd edition of UL 60335-2-89, rather than the earlier UL
standards.
    UL 60335-2-89 includes 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. UL 60335-2-89 was
developed in an open and consensus-based approach, with the assistance
of experts in the AC and refrigeration industry as well as experts
involved in assessing the safety of products. Those participating in
the UL 60335-2-89 consensus standards process have tested equipment for
flammability risk and evaluated the relevant scientific studies. While
similar standards exist from other bodies such as the International
Electrotechnical Commission (IEC), we are proposing 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 listing
determinations for flammable refrigerants (e.g., 76 FR 78832, December
20, 2011; 80 FR 19454, April 10, 2015; 86 FR 24444, May 6, 2021; and 87
FR 45508, July 28, 2022).
    A summary of the requirements of UL 60335-2-89 as they affect the
proposed refrigerants and end-uses is offered here for information only
and does not provide a complete review of the requirements in this
standard.
    The requirements in UL 60335-2-89 reduce the risk to workers and
consumers posed by flammable refrigerants. UL 60335-2-89 limits the
amount of refrigerant allowed in each type of appliance based on
several factors explained in that standard. The standard specifies
requirements for installation space of an appliance (e.g., 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. Annex DVU provides guidance on how to apply the
requirements to allow for safe use of A2L refrigerants. The 2nd edition
of UL 60335-2-89 contains provisions for safety mitigation when using
larger charges of A2L refrigerants or when using A2L refrigerants in
equipment with a remote compressor. 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 measures are required. In certain applications,
refrigerant detection systems (as described in Annex 101.DVP,
Refrigerant detection systems for A2L refrigerants); mitigation means
(as described in Annex 101.DVU, including air circulation, ventilation,
shut off valves, etc.); and refrigerant sensors (as described in
101.DVP, Refrigerant sensor for REFRIGERANT DETECTION SYSTEMS) are
required. Where air circulation (i.e., fans) is required in accordance
with Annex 101.DVU, 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 101.DVU1.7
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 101.DVU, UL 60335-2-89 has a requirement for
the maximum charge for an appliance using a flammable refrigerant,
including A2L, A2, and A3 refrigerants. Additional requirements exist
for charge sizes exceeding three times the LFL.
    Systems with refrigerant charges exceeding certain amounts are
outside the scope of UL 60335-2-89; however, national standards apply
instead, namely, ASHRAE 15-2022. Specifically, if the refrigeration
circuit with the greatest mass of an A2L 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 UL 60335-2-89. In such situations, the refrigerant would
need to be used in outdoor equipment or in a machinery room and the
installation would need to meet the requirements of ASHRAE 15-2022. For
self-contained equipment using an A3 refrigerant, the maximum charge
size is 13 times the LFL (500 g of R-290) for equipment that is open
and contains no doors or drawers and eight times the LFL (300 g of R-
290) for equipment with doors or drawers. EPA expects that many types
of retail refrigeration equipment could exceed these charge thresholds
and therefore is proposing that an additional safety standard, ASHRAE
15-2022, apply to commercial refrigeration equipment using A2L
refrigerants, as discussed in section II.A. Certain key provisions of
ASHRAE 15-2022 are described above in section II.A; that standard
supplements, rather than replaces, UL 60335-2-89, by providing
instructions for installation of equipment and requirements for
situations beyond the scope of UL 60335-2-89, e.g., for use in
refrigeration

systems with large charge sizes in a machinery room or outdoors.
Warning Labels--Equipment With A2L Refrigerants
    As a use condition or revision to existing use conditions, EPA is
proposing to require labeling of refrigerating systems used in retail
food refrigeration equipment, commercial ice machines, IPR equipment,
cold storage warehouses, and ice skating rinks (``equipment'')
containing the proposed lower flammability (A2L) refrigerants. The text
of these labels can also be found in Annex 101.DVV of UL 60335-2-89.
EPA is proposing 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:
    1. On the outside of the unit: ``WARNING--Risk Of Fire. Flammable
Refrigerant Used. To Be Repaired Only By Trained Service Personnel. Do
Not Puncture Refrigerant Tubing''
    2. On the outside of the equipment: ``WARNING--Risk of Fire.
Dispose of Properly In Accordance With Federal Or Local Regulations.
Flammable Refrigerant Used''
    3. 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''
    4. 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 stand-alone units, self-contained commercial
ice machines, and self-contained refrigerated food processing and
dispensing equipment would be packaged, and hence this label would be
placed as stipulated in item 1 above. EPA expects that other types of
commercial refrigeration equipment could be provided packaged or not,
and this label would be placed as stipulated in item 1 or 2,
respectively.
    5. On indoor unit 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 2nd edition of UL 60335-2-89. 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 5.1. above or at the top of the marking if
5.1. 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 floor 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.
    6. For non-fixed equipment, including on the outside of the
appliance: ``WARNING--Risk of Fire or Explosion--Store in a well-
ventilated room without continuously operating flames or other
potential ignition.''
    7. 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.''
    Labeling requirements 1., 2., and 3. above apply to all
refrigeration equipment; labeling requirement 4. applies only to self-
contained equipment that is pre-charged by the manufacturer (e.g.,
stand-alone units or self-contained commercial ice machines); labeling
requirement 5. applies only to equipment with a remote compressor, also
called a ``split'' or ``remote'' system (e.g., remote condensing unit,
supermarket system, or refrigerating system for an ice skating rink
with a remote compressor). A piece of refrigeration equipment that may
be moved from one location to another and is typically self-contained
is referred to as ``non-fixed'' in labeling requirement 6. (e.g.,
stand-alone units).
    EPA notes that Annex 101.DVV of UL 60335-2-89 specifies that the
labels must include text with a font size that is no less than 3.2 mm
(\1/8\ inch) high for A2L refrigerants, while the Agency is proposing a
larger, more visible font size of 6.4 mm (\1/4\ inch). The Agency is
concerned that it is difficult to see warning labels with the minimum
lettering height requirement of \1/8\ inch in UL 60335-2-89. Therefore,
as in the requirements in our previous rules for use of A2L
refrigerants in residential and light commercial air conditioning and
heat pumps (80 FR 19453, April 10, 2015; 86 FR 24444, May 6, 2021), as
well as our previous rules for HC refrigerants (76 FR 78832, December
20, 2011; 80 FR 19453, April 10, 2015; 81 FR 86778, December 1, 2016),
EPA is proposing to require the minimum height for lettering must be
\1/4\ inch as opposed to \1/8\ inch. This would make it easier for
technicians, consumers, retail storeowners, and first responders to
view the warning labels.
Warning Labels--Equipment With A3 Refrigerants, Including R-290
    As a proposed use condition for refrigerated food processing and
dispensing equipment and a proposed revision to existing use conditions
for stand-alone units and commercial ice machines, EPA is proposing to
require labeling of such equipment containing R-290. The text of these
labels can also be found in Annex 101.DVV of UL 60335-2-89. EPA is
proposing 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:
    1. On the outside of the unit: ``DANGER''--Risk Of Fire Or
Explosion. Flammable Refrigerant Used. To Be Repaired Only By Trained
Service Personnel. Do Not Puncture Refrigerant Tubing''.
    2. On the outside of the equipment: ``WARNING--Risk of Fire or
Explosion. Dispose of Properly In Accordance With Federal Or Local
Regulations. Flammable Refrigerant Used''.
    3. On the inside of the equipment near the compressor: ``DANGER--
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''.
    4. For any equipment pre-charged at the factory, on the equipment
packaging or on the outside of the equipment: ``DANGER--Risk of Fire or
Explosion 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 stand-alone units and self-contained
commercial ice machines and self-contained refrigerated food processing
and dispensing equipment would be packaged, and hence this label would
be placed as stipulated in item 1 above. EPA expects that other types
of commercial refrigeration equipment

could be provided packaged or not, and this label would be placed as
stipulated in item 1 or 2, respectively.
    5. On indoor unit 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 2nd edition of UL 60335-2-89. 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 5.1. above or at the top of the marking if
5.1. 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.
    6. For non-fixed equipment, including on the outside of the
appliance: ``WARNING--Risk of Fire or Explosion--Store in a well-
ventilated room without continuously operating flames or other
potential ignition.''
    7. For fixed equipment that is ducted, near the nameplate:
``WARNING--Risk of Fire or Explosion--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, is exactly the same as that
required in UL 60335-2-89, with the exception of the label identified
in 5., which is similar to that in UL 60335-2-89. The text for A3
refrigerants differs slightly from that for A2L refrigerants, sometimes
using the word ``DANGER'' instead of ``WARNING,'' and sometimes
referring to ``Risk of Fire or Explosion'' instead of ``Risk of Fire.''
For R-290 and other A3 refrigerants, UL 60335-2-89 requires the labels
to be no less than 6.4 mm (\1/4\ inch) high in the standard, the same
as EPA is proposing in this action. As in the requirements in our
previous rules for A3 refrigerants (i.e., 76 FR 78832, December 20,
2011; 80 FR 19454, April 10, 2015; and 81 FR 86778, December 1, 2016),
EPA is proposing that the minimum height for lettering be \1/4\ inch,
which would make it easier for technicians, consumers, retail
storeowners, first responders, and those disposing the appliance to
view the warning labels.
Markings
    EPA is proposing to require as a use condition that the
refrigerants must be used in refrigerating equipment that has red,
Pantone[supreg] Matching System (PMS) #185 or RAL 3020 marked pipes,
hoses, and other devices through which the refrigerant is serviced,
typically known as the service port, to indicate the use of a flammable
refrigerant. This color must be present at all service ports and where
service puncturing or otherwise creating an opening from the
refrigerant circuit to the atmosphere might be expected (e.g., process
tubes). The color mark must extend at least 2.5 centimeters (1 inch)
from the compressor and must be replaced if removed. EPA has applied
this same use condition in past actions for flammable refrigerants (76
FR 78832, December 20, 2011; 80 FR 19454, April 10, 2015; 81 FR 86778,
December 1, 2016; 86 FR 24444, May 6, 2021; and 87 FR 45508, July 28,
2022). Our understanding of UL 60335-2-89 is that red markings similar
to those proposed are required by UL 60335-2-89 for all flammable
refrigerants. EPA is proposing that such markings apply to the proposed
listings for flammable refrigerants as well to establish a common,
familiar, and standard means of identifying the use of a flammable
refrigerant.
    These red markings would help technicians immediately identify the
use of a flammable refrigerant, thereby 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 in SNAP listings, color-coded hoses or
pipes must be used for ethane, HFC-32, R-452B, R-454A, R-454B, R-454C,
R-457A, R-600a, R-290, 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. The intent of this aspect of
the proposal is to alert 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 SNAP Rule
19, 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
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 proposing 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 believes having two such warning
methods is 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;
80 FR 19454, April 10, 2015; 86 FR 24444, May 6, 2021; and 87 FR 45508,
July 28, 2022).
    EPA also is proposing to add a new marking to be placed near the
service port or other location where charging occurs; on the label on
the outside of the unit; and either on the appliance packaging, if the
refrigeration equipment is charged at the factory or on the nameplate
or control panel for refrigeration equipment that is charged in place.
These locations correspond with the locations for red markings and for
the labels 1. and 4. mentioned above on the outside of the
refrigerating unit, and either on the packaging, or on the nameplate or
control panel. UL 60335-2-89 describes markings in section 7, including
a triangular symbol with a white picture of a flame on a red
background, similar in size and shape to that of the International
Organisation for Standardisation (ISO) symbol 7000-W021, but with
different coloration (Clause 7.6DV D1). EPA is proposing a new diamond
symbol for ``Caution, risk of fire'' that would be used in addition to
the red triangle in Clause 7.6DV D1 of UL 60335-2-89. The diamond
symbol hazard category 1 flammable gases would need to be at least 15
mm (9/16 inches) high.
    EPA understands that in consultation with different fire service
groups, such as the International Association of Fire

Fighters, UL and its standard-setting committees have been considering
appropriate symbols to alert first responders to the presence and
potential hazards of flammable refrigerant. One symbol under
consideration is an equal-sided diamond with a red outline and a flame
symbol on a white background, together with the refrigerant class from
ASHRAE 34-2022 (e.g., A2L or A3) to be written in text not less than
one-third of the height of the symbol. This symbol is included as the
warning symbol for hazard category 1 flammable gases in the 9th edition
of the GHS for communicating risks of chemicals.\73\ This symbol for
hazard category 1 flammable gases is included in the 4th edition of UL
60335-2-40 (December 2022), UL's most recent safety standard for air
conditioning equipment, heat pumps, and humidifiers, and is being
considered for adoption in the future 3rd edition of UL 60335-2-89. It
is found in section 1.2 of Annex 1 of the 9th edition of the GHS. You
may see the proposed symbol for hazard category 1 flammable gases in
the docket for this rulemaking under the title, ``Proposed Flammability
Hazard Symbol.''
---------------------------------------------------------------------------

    \73\ GHS, 2021. GHS Pictogram for Hazard Category 1 Flammable
Gases from Annex 1 to the 9th edition of the Global Harmonized
System of Classification and Labelling of Chemicals, 2021. You may
find the GHS document online at https://unece.org/sites/default/files/2021-9/GHS_Rev9E_0.pdf or from the United Nations Publications
section at: https://shop.un.org/books/global-harmon-syst-class-9-92280.
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    EPA is proposing to add this symbol to ensure the adoption of a
symbol for ``Caution, risk of fire'' that is likely to be recognized by
first responders in the United States as well as internationally. The
symbol ISO 7000-W021, used in other UL standards for refrigerating
equipment, is a black flame symbol on a yellow triangle. U.S.
organizations representing fire fighters have raised concerns about
that symbol, since it could refer to a highly reactive oxidizer, rather
than a flammable substance. This is relevant because first responders
would take different actions for an oxidizer from those for a flammable
substance. EPA is proposing to include the GHS diamond symbol for
hazard category 1 flammable gases prior to UL's adoption of it in UL
60335-2-89 to provide an additional warning about flammability hazard
that is more likely to be recognizable by first responders and
internationally than the current symbol in UL 60335-2-89.
2. What additional information is EPA including in these proposed
listings?
    For retail food refrigeration, commercial ice machines, IPR, cold
storage warehouses, and ice skating rinks with remote compressors, EPA
is proposing to include recommendations, 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 proposing to include 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.
3. On which topics is EPA specifically requesting comment?
    EPA is requesting comment on all aspects of the proposed use
conditions described above and the appropriateness for applying these
use conditions to the listings for A2L refrigerants used in retail food
refrigeration, commercial ice machines, IPR and chillers for IPR, cold
storage warehouses, and ice skating rinks with remote compressors in
sections II.A, II.C, II.E, II.F, and II.G, respectively.
    EPA is requesting comment on all aspects of the proposed use
conditions described above and the appropriateness for applying these
use conditions to the listing for R-290 used in refrigerated food
processing and the proposed revisions to the use conditions in existing
listings for R-290 in stand-alone units and self-contained commercial
ice machines in sections II.B and II.D.
    EPA is requesting comment on the applicability of UL 60335-2-89 to
commercial refrigeration equipment, including for which types of
equipment and under which applications the standard applies. We
likewise are requesting comment on the applicability of UL 60335-2-89
to commercial ice machines, IPR equipment, cold storage warehouses, and
ice skating rinks with remote compressors.
    Also, with regard to UL 60335-2-89, EPA is requesting comment on
the status of the standard, the modifications that are being or have
been incorporated in it, how those modifications would change the risk
associated with the use of the proposed flammable refrigerants in these
end-uses, and the appropriateness of adopting as a use condition the
current (2nd) edition of this standard.
    EPA is also requesting comment on requiring labeling, the height of
the lettering, the proposed diamond symbol for hazard category 1
flammable gases, and the likelihood of labels remaining on a product
throughout the lifecycle of the product, including its disposal.

I. Proposed Exemption for R-290 From the Venting Prohibition Under CAA
Section 608 for Refrigerated Food Processing and Dispensing Equipment.

1. What is EPA's proposed determination regarding whether venting,
releasing, or disposing of R-290 in refrigerated food processing and
dispensing equipment would pose a threat to the environment?
    As described in section I.A above, under section 608(c)(2) of the
CAA, it is unlawful for any person, in the course of maintaining,
servicing, repairing, or disposing of an appliance or industrial
process refrigeration, to knowingly vent or otherwise knowingly release
or dispose of any substitute substance for a class I or class II
substance used as a refrigerant in such appliance (or industrial
process refrigeration) in a manner which permits such substance to
enter the environment. Under section 608(c)(2), this prohibition
applies to any substitute refrigerant unless the Administrator
determines that such venting, releasing, or disposing does not pose a
threat to the environment. As discussed in section II.B above, EPA is
proposing to list the refrigerant substitute R-290 under the SNAP
program as acceptable, subject to use conditions, in newly manufactured
refrigerated food processing and dispensing equipment. EPA is also
proposing to exempt R-290 in this end-use from the venting prohibition
under CAA section 608(c)(2), on the basis of current evidence that the
venting, release, or disposal of this substance in this end-use and
subject to the use conditions in this proposed action does not pose a
threat to the environment.
    For purposes of CAA section 608(c)(2), EPA considers two factors in
determining whether or not venting, release, or disposal of a
refrigerant substitute during the maintenance, servicing, repairing, or
disposing of appliances poses a threat to the environment. See 69 FR
11948, March 12, 2004; 79 FR 29682, May 23, 2014; 80 FR 19453, April
10, 2015; and 81 FR 86778, December 1, 2016. First, EPA analyzes the
threat to the environment due to inherent characteristics of the

refrigerant substitute, such as GWP or photochemical reactivity.
Second, EPA determines whether and to what extent venting, release, or
disposal actually takes place during the maintenance, servicing,
repairing, or disposing of appliances, and to what extent such actions
are controlled by other authorities, regulations, or practices. To the
extent that such releases are adequately controlled by other
authorities, EPA defers to those authorities.
Potential Environmental Impacts
    EPA has evaluated the potential environmental impacts of releasing
R-290 into the environment, a substitute that we are proposing to list
under the SNAP program as acceptable, subject to use conditions, in
refrigerated food processing and dispensing equipment. We assessed the
potential impact of the release of R-290 on local air quality and its
ability to decompose in the atmosphere to form ground-level ozone, its
ODP, its GWP, and its potential impacts on ecosystems. We found that
the sizes of these impacts were not large enough to pose a threat to
the environment. R-290's ODP is zero and its GWP is approximately
three. R-290 is highly volatile and typically evaporates or partitions
to air, rather than contaminating surface waters. Thus, R-290's effects
on aquatic life are expected to be small.
    As to potential effects on local air quality, R-290 meets the
definition of VOC under CAA regulations (see 40 CFR 51.100(s)) and is
not excluded from that definition for the purpose of developing SIPs to
attain and maintain the NAAQS. R-290's maximum incremental reactivity
(MIR) of 0.56 g O3/g R-290 is higher and more reactive than
that of the compound ethane (MIR of 0.26 g O3/g ethane),
which EPA uses as a threshold to determine whether substances may have
negligible photochemical reactivity in the lower atmosphere
(troposphere). EPA performed air quality modeling on a number of
scenarios to determine if emissions of HC refrigerants could have a
significant impact on local air quality, particularly in certain cities
with particularly difficult challenges in achieving attainment of the
NAAQS for ground-level ozone. Based on the analysis and modeling
results described in section II.B.3, EPA proposes to conclude that the
release of R-290 from the refrigerated food processing and dispensing
end-use, in addition to the HCs previously listed as acceptable,
subject to use conditions, for their specific end-uses, is expected to
have little impact on local air quality. In this regard, EPA found
particularly noteworthy that even assuming 100 percent market
penetration of R-290 and the other acceptable HCs in the acceptable
end-uses, which is a conservative assumption, the highest impact for a
single 8-hour average ozone concentration based on that analysis would
be 0.05 ppb in Los Angeles, 0.008 in Houston, and 0.005 in Atlanta
compared to the NAAQS at 70 ppb.\74\
---------------------------------------------------------------------------

    \74\ ICF, 2016. Additional Follow-on Assessment of the Potential
Impact of Hydrocarbon Refrigerants on Ground Level Ozone
Concentrations. September, 2016.
---------------------------------------------------------------------------

    In addition, when examining all HC substitute refrigerants in those
uses for which UL currently has standards in place, for which the SNAP
program has already listed the uses as acceptable, subject to use
conditions, or for which the SNAP program is reviewing a submission,
including those in this proposed action, we found that even if all the
HC refrigerant substitutes in appliances in end-uses proposed to be
listed acceptable, subject to use conditions, in this action and listed
as acceptable in previous rules were to be emitted, there would be a
worst-case impact of less than 0.15 ppb for ground-level ozone in the
Los Angeles area.\75\ The use conditions established in the prior SNAP
listings limited the total amount of R-290 in each refrigerant circuit
to 60 g or less (for water coolers) or 150 g or less (for other end-
uses), depending on the end-use. Because R-290 is not listed as
acceptable for use in all refrigerant uses, the total amount of R-290
that could be emitted in the end-uses evaluated is estimated at roughly
ten percent of total refrigerant emissions, or less than 16,000 metric
tons annually.\76\ In comparison, total anthropogenic VOC emissions
were estimated at 19.6 million metric tons in 2017.\77\ Further, there
are other substitute refrigerants that are not VOC that may also be
used in these end-uses, so our analysis assuming complete market
penetration of HCs is conservative.
---------------------------------------------------------------------------

    \75\ ICF, 2014a. Assessment of the Potential Impact of
Hydrocarbon Refrigerants on Ground Level Ozone Concentrations.
February 2014.
    \76\ Ibid.
    \77\ U.S. EPA, 2020. 2017 National Emissions Inventory Report.
U.S. Environmental Protection Agency. Available online at https://gispub.epa.gov/neireport/2017/.
---------------------------------------------------------------------------

    EPA also has performed more recent air quality analysis,
considering additional end-uses and refrigerants that have been listed
acceptable more recently (e.g., R-1150 in very low temperature
refrigeration), looking out to 2040, and using updated models.\78\ EPA
found that the revised air quality models showed slightly greater
impacts compared to our 2014 and 2016 analyses in all scenarios. For
example, in the worst-case scenarios where the most reactive HC
refrigerant, propylene, was used broadly across the refrigeration and
AC industry, the worst-case increase in ground-level ozone was 8.62 ppb
in Los Angeles in the 2020 analysis compared to 7.8 ppb in Los Angeles
in an analysis in 2016 looking at the same scenario with the same
refrigerant. Changes to the Community Multiscale Air Quality (CMAQ)
model, more updated refrigerant emissions estimates from EPA's
Vintaging Model, as well as the longer time-period considered, resulted
in the changes. The 2016 analysis found that even assuming 100 percent
market penetration of R-290 and the other acceptable HCs in the end-
uses where they are already listed as acceptable, subject to use
conditions, or were under review, which is a conservative assumption,
the highest impact for a single 8-hour average ozone concentration
based on the 2016 analysis would be 0.05 ppb in Los Angeles and less
than 0.01 ppb in Houston and Atlanta.\79\ Looking at the 2020 analysis,
in the scenarios that estimated emissions assuming that HC refrigerants
listed as acceptable, subject to use conditions, reached 100 percent
market penetration, the worst-case increase in ground-level ozone in
Los Angeles was 0.012 ppb, in Houston was 0.009 ppb, and in Atlanta was
0.006 ppb. Unlike the 2016 analysis, the 2020 analysis did not include
modeling of propylene or the propylene blend R-443A in certain end-
uses, as those refrigerants were listed as unacceptable in SNAP Rule 21
(81 FR 86778, December 1, 2016). The modeled changes to ground-level
ozone levels were less than 0.017 percent of the NAAQS 8-hour ozone
concentration of 70 ppb.\80\ EPA considers this to further support the
Agency's earlier conclusions in 2015 and 2016 that use of saturated HCs
as refrigerants, including release of R-290, R-600a, and R-441A during
repairing, maintaining, servicing, or disposing of appliances, would
not result in a significant increase in ground-level ozone.
---------------------------------------------------------------------------

    \78\ ICF, 2020. Additional Assessment of the Potential Impact of
Hydrocarbon Refrigerants on Ground Level Ozone Concentrations. May
2020. Updated models included VM IO file_v5.1_10.01.19 and CMAQ
5.2.1 with carbon bond 06 (CB06) mechanism, as cited in ICF, 2020.
    \79\ ICF, 2016. Additional Follow-on Assessment of the Potential
Impact of Hydrocarbon Refrigerants on Ground Level Ozone
Concentrations. September 2016.
    \80\ ICF, 2020. Op cit.

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

    Considering our evaluation of these potential environmental
impacts, EPA proposes to conclude that R-290 in the refrigerated food
processing and dispensing end-use is not expected to pose a threat to
the environment on the basis of the inherent characteristics of this
substance and the limited quantities used in the relevant end-use.
Authorities, Controls, or Practices
    EPA expects that existing authorities, controls, and/or practices
will mitigate environmental risk from the release of R-290. Analyses
performed for both this rule and the SNAP rules issued in 1994, 2011,
2015, 2016, and 2022 (59 FR 13044, March 17, 1994; 76 FR 38832,
December 20, 2011; 80 FR 19453, April 10, 2015; and 81 FR 86778,
December 1, 2016, respectively) indicate that existing regulatory
requirements and industry practices limit and control the emission of
R-290. As explained below, EPA proposes that the limits and controls
under other authorities, regulations, or practices adequately control
the release of and exposure to R-290 and mitigate risks from any
possible release.
    As mentioned above, the determination of whether venting, release,
or disposal of a substitute refrigerant poses a threat to the
environment includes considering whether such venting, release, or
disposal is adequately controlled by other authorities, regulations, or
practices. This information is another part of EPA's proposal that the
venting, release, or disposal of R-290, in the specified end-use and
subject to the use conditions in this proposed action, does not pose a
threat to the environment.
    Industry service practices and OSHA standards and guidelines that
address HC refrigeration equipment include monitoring efforts,
engineering controls, and operating procedures. OSHA requirements that
apply during servicing include continuous monitoring of explosive gas
concentrations and oxygen levels. In general, HC emissions from
refrigeration systems are likely to be significantly smaller than those
emanating from the industrial process and storage systems, which are
controlled for safety reasons. In sections II.B.7, ``What updates to
existing use conditions for stand-alone units is EPA proposing?'' and
II.D.5, ``What updates to existing use conditions for commercial ice
machines is EPA proposing?'' above in this document, we note that the
amount of substitute refrigerant from a refrigerant loop is effectively
limited to 500 g or 300 g in the end-uses proposed in this rule. This
indicates that HC emissions from such uses are likely to be relatively
small.
    As discussed above in section II.B.3, ``What is R-290 and how does
it compare to other refrigerants in the refrigerated food processing
and dispensing equipment end-use category?'', EPA's SNAP program
evaluated the flammability and toxicity risks from R-290 in the
proposed new end-use in this rule. EPA is providing some of that
information in this section as well, to provide information on the
potential for leaks and exposure due to R-290.
    R-290 is classified as an A3 refrigerant by ASHRAE 34-2022 and
subsequent addenda, indicating that it has low toxicity and high
flammability. R-290 has an LFL of 2.1 percent. To address flammability
risks, this proposal provides recommendations for its safe use (see
section II.H.2, ``What additional information is EPA including in these
proposed listings?''). The SNAP program's analysis suggests that the
proposed use conditions in this rule will mitigate flammability risks.
    Like most refrigerants, at high concentrations HCs can displace
oxygen and cause asphyxiation. Various industry and regulatory
standards exist to address asphyxiation and toxicity risks. The SNAP
program's analysis of asphyxiation and toxicity risks suggests that the
proposed use conditions in this rule would mitigate asphyxiation and
toxicity risks. Furthermore, it is the Agency's understanding that
flammability risks and occupational exposures to HCs are adequately
regulated by OSHA and building and fire codes at a local and national
level.
    The release and/or disposal of many refrigerant substitutes,
including R-290, are controlled by other authorities including various
standards and state and local building codes. The industry consensus
safety standard UL 60335-2-89, which EPA is proposing to incorporate by
reference in use conditions in the SNAP listing for R-290 in
refrigerated food processing and dispensing equipment, is one of these
standards, and industry also applies the standard ASHRAE 15. Code-
making organizations, such as the International Code Council (ICC), are
in the process of updating references to the most recent industry
standards that address use of R-290 and other flammable refrigerants in
the International Building Code (IBC). The specific editions of UL
60335-2-89 and ASHRAE 15-2022 are in the process of being adopted in
the next version of the IBC; once the IBC adopts those standards,
states and localities may adopt those revisions into their state or
local building codes. To the extent that release during maintaining,
repairing, servicing, or disposing of appliances is controlled by
regulations and standards of other authorities, these practices and
controls for the use of R-290 are sufficiently protective. These
practices and controls mitigate the risk to the environment that may be
posed by the venting, release, or disposal of R-290 during the
maintaining, servicing, repairing, or disposing of appliances.
    EPA is aware of equipment that can be used to recover HC
refrigerants. While there are no relevant U.S. standards for such
recovery equipment currently, to the extent that R-290 is recovered
rather than vented in specific end-uses and equipment, EPA recommends
the use of recovery equipment designed specifically for flammable
refrigerants in accordance with applicable safe handling practices.
2. What is EPA's proposal regarding whether venting of R-290 from
refrigerated food processing and dispensing equipment should be
exempted from the venting prohibition under CAA section 608(c)(2)?
    Consistent with the proposed listing under SNAP in this action, EPA
proposes to determine that venting, releasing, or disposing of R-290 in
refrigerated food processing and dispensing equipment is not expected
to pose a threat to the environment during the maintaining, servicing,
repairing, or disposing of appliances. As discussed more fully above,
we propose this on the basis of the inherent characteristics of this
substance, the limited quantities used in the relevant end-uses, and
the limits and controls under other authorities, regulations, or
practices that adequately control the release of and exposure to R-290
and mitigate risks from any possible release. Accordingly, EPA is
proposing to revise the regulations at Sec.  82.154(a)(1) to add R-290
in this end-use to the list of substitute refrigerants that are exempt
from the venting prohibition under CAA section 608(c)(2).
3. When would the exemption from the venting prohibition apply?
    We are proposing that this exemption for R-290 in refrigerated food
processing and dispensing equipment would apply as of 30 days after the
publication of a final rule in the Federal Register. This would be the
same as the proposed effective date of the SNAP listing of R-290 in
refrigerated food processing and dispensing equipment, if that listing
is finalized as proposed.

4. What is the relationship between this proposed exemption under CAA
section 608(c)(2) and other EPA rules?
    If this proposed exemption were to become final as proposed, it
would not mean that R-290 could be vented in all situations. R-290 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 260 through 270). As discussed in
the final rules addressing the venting of ethane (R-170), R-600a, R-
290, and R-441A as refrigerant substitutes in certain end-uses,
incidental releases may occur during the maintenance, service, and
repair of appliances subject to CAA section 608 (79 FR 29682, May 23,
2014; 80 FR 19454, April 10, 2015; 81 FR 86778, December 1, 2016). Such
incidental releases would not be subject to RCRA requirements for the
disposal of hazardous waste, as such releases would not constitute
disposal of the refrigerant charge as a solid waste, per se. For
commercial appliances such as refrigerated food processing and
dispensing equipment, it is likely that R-290 and other flammable HC
refrigerant substitutes would be classified as hazardous waste and
recycling, reclamation or disposal of R-290 from such appliances would
need to be managed as hazardous waste under the RCRA regulations (40
CFR parts 260 through 270), unless it is subject to a limited exception
in those regulations if the ignitable refrigerant is to be reused
without first being processed to remove contamination.
5. On which topics is EPA specifically requesting comment?
    EPA requests comment on all aspects of our proposal to exempt R-290
used as a refrigerant substitute in refrigerated food processing and
dispensing equipment from the venting prohibition under CAA section
608(c)(2), as well as seeking comment on the proposed addition to the
existing exemption language for R-290 in particular end-uses at 40 CFR
82.154(a)(1)(viii). The Agency notes that the proposed regulatory text
contains the proposed addition to Sec.  82.154(a)(1)(viii), as well as
certain other exemptions for other end-uses that already appear at 40
CFR 82.154(a)(1)(viii) and that EPA is republishing for purposes of
formatting for the Federal Register. EPA is not proposing changes to,
and is not taking comment on, those existing exemptions and we are not
reopening for comment those current exemptions for the other end-uses
where R-290 may be used.

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)

    This action does not impose any new information collection burden
under the 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 proposed rule contains no new requirements for
reporting or recordkeeping.

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 proposed 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 proposes to add the additional options under SNAP of
using HFC-32, HFO-1234yf, HFO-1234ze(E), R-290, R-454A, R-454B, R-454C,
R-455A, R-457A, and R-516A in the specified end-uses, but does not
mandate such use. Because equipment for HFO-1234yf, HFO-1234ze(E), R-
454A, R-454B, R-454C, R-455A, R-457A, and R-516A is not manufactured
yet in the U.S. for retail food refrigeration equipment, commercial ice