1b** estimates propylene's emissions using EPA's Vintaging Model (VM)
and Community Multi-stage Air Quality (CMAQ) model,\34\ and Scenario 1b
estimates R-1150's emissions using the same VM and CMAQ versions as in
Scenario 1b.**
---------------------------------------------------------------------------

    \32\ Ibid.
    \33\ EPA is aware that such refrigeration equipment exists in
Europe. Thus, EPA evaluated R-1150 in retail food refrigeration--
stand-alone units as well as in VLTR and other hydrocarbon
refrigerants, to consider the greatest impact that reasonably could
occur when using increasing amounts of such refrigerants.
    \34\ VM IO file_v5.1_10.01.19 and CMAQ 5.2.1 with carbon bond 06
(CB06) mechanism, as cited in ICF, 2022p. Additional Assessment of
the Potential Impact of Hydrocarbon Refrigerants on Ground Level
Ozone Concentrations. May, 2020.
---------------------------------------------------------------------------

    Additionally, the analysis also considers the more realistic
scenarios (Scenario 2, Scenario 3a, and Scenario 3b) where HCs are
modeled only in the end-uses where the SNAP program has already listed
them as acceptable, or for which SNAP submissions or international
market trends indicate HCs soon could be used. Scenario 2 examines the
likely emissions of lower maximum incremental reactivity (MIR) HCs,
propane, isobutane, and ethane, in the residential and light commercial
AC, residential dehumidifiers, retail refrigeration, and household
refrigeration end-uses. Scenarios 3a and 3b also consider the use of
higher MIR refrigerants propylene and R-1150 in laboratory equipment
(IPR and VLTR end-uses, respectively) and R-1150 in small retail food
refrigeration equipment (e.g., stand-alone units) in addition to the
HCs used in Scenario 2. Scenarios 3a and 3b differentiate based on
whether propylene and R-1150 would be subject to the prohibition under
CAA sections 608(c)(1) and (2) against knowingly venting or otherwise
knowingly releasing or disposing of any refrigerant substitute for
class I or class II substances by any person maintaining, servicing,
repairing, or disposing of appliances or IPR. For further information
on the specific assumptions, see the docket for this rulemaking.\35\
---------------------------------------------------------------------------

    \35\ ICF, 2022p. Additional Assessment of the Potential Impact
of Hydrocarbon Refrigerants on Ground Level Ozone Concentrations.
May, 2020.
---------------------------------------------------------------------------

    In highly conservative Scenario 1b, examining widespread R-1150
adoption across the refrigeration and AC sector, modeling predicts that
the single 8-hour average ground-level ozone concentration could
increase by 11.7 percent in Los Angeles, which is the area with the
highest level of ground-level ozone pollution in the United States.
However, in the more realistic scenarios 3a and 3b, 8-hour ground-level
ozone concentration in Los Angeles was found to increase by a maximum
of 0.017 percent relative to the NAAQS on the worst modeled day. For
purposes of this SNAP determination, this is not a significant increase
in ground-level ozone. The modeling is also conservative by assuming a
one-for-one substitution of HCs for current refrigerants because an
actual transition would likely introduce less than one kg of HC for
each kg replaced. As a result of this analysis, EPA believes that the
use of R-1150 consistent with the use conditions and narrowed use
limits proposed would not result in significantly greater risk to
people's health or the environment than other alternatives available
for the same use.
    Ecosystem effects from R-1150 are expected to be small, as are the
effects of other acceptable substitutes in this end-use. R-1150 is
highly volatile and typically evaporates or partitions to air, rather
than contaminating ground or surface waters, and thus R-1150's effects
on aquatic life are expected to be small. Based on these
considerations, R-1150 is not expected to pose a greater risk of
ecosystem effects than other alternatives for these uses.
    Flammability information: ASHRAE Standard 34 classifies R-1150 as a
Class A3 refrigerant.\4\ R-1150 is flammable when its concentration in
the air is in the range of 2.7 percent to 36 percent by volume (27,000
ppm to 360,000 ppm).4 30
    Toxicity and exposure data: Exposure to R-1150 may be hazardous if
inhalation, skin contact, or eye contact with the proposed substitute
occurs at sufficiently high levels. The most likely pathway of exposure
is through inhalation, which can cause symptoms of asphyxiation.
Exposures of R-1150 to the skin may cause frostbite. Exposures of R-
1150 to the eyes could cause eye irritation. These potential health
effects are common to many refrigerants.
    The American Conference of Governmental Industrial Hygienists
(ACGIH) has established a TLV of 200 ppm as an 8-hour TWA for R-1150.
EPA anticipates that users will be able to meet the TLV and address
potential health risks by following the use condition limiting charge
sizes to 150 g and the requirements and recommendations in the
manufacturer's SDS, ASHRAE Standard 15, UL Standard 61010-2-011, 2nd
Edition, and other safety precautions common to the refrigeration and
AC industry.3 30
    Comparison to other substitutes in this end-use: R-1150 has an ODP
of zero, comparable to or less than other listed substitutes in this
end-use with ODPs ranging from zero to 0.098. For new VLTR equipment,
R-1150's GWP of four is comparable to that of other acceptable
substitutes such as ethane and CO2, with respective GWPs of
5.5 and one, and lower than other acceptable substitutes such as R-
410A, R-507A, and HFC-23 with respective GWPs of 1,890, 3,990, and
14,800.
    R-1150 is a VOC that is more photochemically reactive and more
likely to cause ground-level ozone pollution than acceptable
refrigerants in this end-use. For example, R-1150 has a MIR of 9.07 g-
O3/g-substance, which is higher than propane's MIR of 0.56
g-O3/g-substance or ethane's MIR of 0.28 g-O3/g-
substance.\36\ EPA proposes to address this potential risk through a
narrowed use limit, restricting use of this refrigerant to VLTR
equipment designed to reach temperatures lower than -80 [deg]C (-112
[deg]F). See section

II.F.6 below for a discussion of the proposed narrowed use limits.
---------------------------------------------------------------------------

    \36\ In addition to being an acceptable refrigerant in very low
temperature refrigeration, ethane's MIR is one threshold that EPA
considers in deciding whether a compound makes a negligible
contribution to tropospheric ozone formation and should be excluded
from EPA's regulatory definition of VOC (see 40 CFR 51.100(s))
addressing the development of SIPs to attain and maintain the NAAQS.
---------------------------------------------------------------------------

    Flammability risks of R-1150 are comparable to flammability risks
of other available substitutes in the same end-use, such as ethane,
while R-1150's flammability risks are higher than those of nonflammable
refrigerants such as R-410A, CO2, or HFC-23. Flammability
risks can be addressed by following the proposed use conditions, such
as use only in new equipment that is designed and tested to meet the UL
Standard 61010-2-011. See section II.F.4 below for a discussion of the
proposed use conditions.
    Toxicity risks are comparable to or lower than toxicity risks of
other available substitutes in the same end-use. Toxicity risks can be
minimized by use consistent with the TLV issued by the ACGIH, ASHRAE
Standard 15, UL standards, and other industry standards,
recommendations in the manufacturer's SDS, and other safety precautions
common in the refrigeration and AC industry.
    Although R-1150 presents a higher risk to local air quality than
other available alternatives for this end-use, other alternatives such
as ethane, propane, and most HFOs or HFCs that are less photochemically
reactive than R-1150 are not able to attain temperatures as low as R-
1150 because of their higher boiling points. Thus, EPA is proposing to
list this substitute as acceptable subject to use conditions and
narrowed use limits in VLTR.
4. What use conditions is EPA proposing?
    EPA proposes the following use conditions to address flammability
risks of R-1150:
    (1) New equipment only--R-1150 may be used only in new equipment
designed specifically and clearly identified for the refrigerant, i.e.,
the substitute shall not be used as a conversion or ``retrofit''
refrigerant for existing equipment.
    (2) UL Standard--R-1150 may be used only in laboratory equipment
that meet all requirements listed in the 2nd edition, dated May 13th,
2021, of UL Standard 61010-2-011, ``Safety Requirements for Electrical
Equipment for Measurement, Control, and Laboratory Use--Part 011:
Particular Requirements for Refrigerating Equipment'' (hereafter in
this section, ``UL Standard''). If this rule is finalized as proposed,
in cases where the final rule would include requirements different than
those of the UL Standard, EPA is proposing that the equipment would
need to meet the requirements of the final rule in place of the
requirements in the UL Standard. Requirements of note include:
     Warning labels--The following markings, or the equivalent,
must be provided in letters no less than 6.4 millimeter (\1/4\ inch)
high and must be permanent:
    i. Attach near the machine compartment: ``DANGER--Risk of Fire or
Explosion. Flammable Refrigerant Used. To Be Repaired Only By Trained
Service Personnel. Do Not Puncture Refrigerant Tubing.''
    ii. Attach near the machine compartment: ``CAUTION--Risk of Fire or
Explosion. Flammable Refrigerant Used. Consult Repair Manual/Owner's
Guide Before Attempting To Service This Product. All Safety Precautions
Must be Followed.''
    iii. Attach on the exterior of the refrigeration equipment:
``CAUTION--Risk of Fire or Explosion. Dispose of Properly In Accordance
With Federal Or Local Regulations. Flammable Refrigerant Used.''
    iv. Attach near all exposed refrigerant tubing: ``CAUTION--Risk of
Fire or Explosion Due To Puncture Of Refrigerant Tubing; Follow
Handling Instructions Carefully. Flammable Refrigerant Used.''
    v. Attach on the exterior of the refrigeration equipment: ``This
equipment is intended for use in commercial, industrial, or
institutional occupancies as defined in the Safety Standard for
Refrigeration Systems, ANSI/ASHRAE 15''.
    vi. Attach on the exterior of the shipping carton: ``CAUTION--Risk
of Fire or Explosion. Dispose of Properly In Accordance With Federal Or
Local Regulations.''
    vii. The instructions shall include the following warnings as
necessary:
    a. ``WARNING: Ensure all ventilation openings are not obstructed.''
    b. ``WARNING: Do not use mechanical devices or other means to
accelerate the defrosting process, other than those recommended by the
manufacturer.''
    c. ``WARNING: Do not damage the refrigerant circuit.''
     Markings--Equipment must have distinguishing red (PMS #185
or RAL 3020) color-coded hoses and piping to indicate use of a
flammable refrigerant. The laboratory equipment shall have marked
service ports, pipes, hoses and other devices through which the
refrigerant is serviced. Markings shall extend at least 1 inch (25
millimeter) from the servicing port and shall be replaced if removed.
    (3) Charge size--Equipment must use no more than 150 g of R-1150 in
each refrigerant circuit using this refrigerant.
    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 X of 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
refrigerant that are not included in the information listed in the
tables (e.g., the CAA section 608(c)(2) prohibition on knowingly
venting or otherwise knowingly releasing or disposing of substitute
refrigerants in the course of maintaining, servicing, repairing or
disposing of an appliance or industrial process refrigeration, or
Department of Transportation requirements for transport of flammable
gases). Flammable refrigerants being recovered or otherwise disposed of
from VLTR appliances are likely to be hazardous waste under the RCRA
(see 40 CFR parts 260-270).
5. Why is EPA proposing these specific use conditions?
    EPA is proposing to list R-1150 as acceptable, subject to use
conditions, for use in the VLTR end-use for new equipment reaching
temperatures lower than -80 [deg]C (-112 [deg]F). The use conditions
are identified in the listing under subheading II.F.4, above, and are
explained here in greater detail. The use conditions EPA proposes
include conditions requiring use of R-1150 in new equipment, which can
be specifically designed for the refrigerant; use consistent with the
UL Standard, including testing, charge sizes, ventilation, usage space
requirements, and certain hazard warnings and markings; and limiting
charge size to 150 g of R-1150 per refrigerant circuit. The listings
with specific use conditions are intended to allow for the use of this
flammable refrigerant in a manner that will ensure it does not pose a
greater overall risk to human health and the environment than other
substitutes in this end-use.

New Equipment Only; Not Intended for Use as a Retrofit Alternative

    EPA is proposing that R-1150 may be used only in new equipment \37\
which has been designed to address concerns unique to flammable
refrigerants--i.e., this substitute may not be used as a conversion or
``retrofit'' refrigerant for existing equipment. EPA is unaware of

information on how to address hazards if this flammable refrigerant
were to be used in equipment that was designed for non-flammable
refrigerants. Given the flammable nature of the refrigerant, the fact
that EPA is unaware of information to assess the risk if such retrofits
were allowed, and because the refrigerant was not submitted to the SNAP
program for retrofits, EPA has not reviewed it for retrofit
applications for this proposal and is only proposing that it may be
used in new equipment which can be properly designed for their use.
Therefore, EPA is proposing that R-1150 may only be used in new
equipment that can be properly designed for its use.
---------------------------------------------------------------------------

    \37\ This is intended to mean a completely new refrigeration
circuit containing a new compressor, evaporator, and condenser.
---------------------------------------------------------------------------

Standards

    EPA is proposing that R-1150 may be used only in equipment that
meets all requirements in the UL Standard. This UL Standard indicates
that refrigerant charges greater than 150 g are beyond its scope and
that additional requirements apply, such as for instance ANSI/ASHRAE
15-2019. EPA has only evaluated equipment that fits within the scope of
the UL Standard.
    UL has developed safety standards including requirements for
construction and system design, for markings, and for performance tests
concerning refrigerant leakage, ignition of switching components,
surface temperature of parts, and component strength after being
scratched. Certain aspects of system construction and design, including
charge size, ventilation, and installation space, and greater detail on
markings, are discussed further below in this section. The UL Standard
was developed in an open and consensus-based approach, with the
assistance of experts in the laboratory equipment industry as well as
experts involved in assessing the safety of products. While similar
standards exist from other bodies such as the IEC, we are proposing to
rely on a specific UL standard that is most applicable and recognized
by the U.S. market. This approach is the same as that in our previous
rules on flammable refrigerants (e.g., 76 FR 78832, December 20, 2011;
80 FR 19454, April 10, 2015; 86 FR 24444, May 6, 2021).
    A summary of the requirements of the UL Standard as they affect R-
1150 and the end-use addressed in this section of our proposal follows.
This summary is offered for information only and does not provide a
complete review of the requirements in this standard. The UL Standard
requires the warning labels on the equipment to contain letters at
least \1/4\ inch high. The label must be permanently affixed to the
equipment. Warning label language requirements are described in section
II.F.4 of this proposed rule. Additionally, red markings, similar to
those EPA has applied as use conditions in past actions for flammable
refrigerants (76 FR 78832, December 20, 2011; 80 FR 19454, April 10,
2015; 86 FR 24444, May 6, 2021), are required by the UL Standard for A2
and A3 refrigerants to establish a common, familiar and standard means
of identifying the use of a flammable refrigerant.
    These red markings will help technicians immediately identify the
use of a flammable refrigerant, thereby potentially reducing the risk
of using sparking equipment or otherwise having an ignition source
nearby. The colored plastic sleeve or cap would have to be forcibly
removed in order to access the service port, hose, or pipe. This would
signal to the technician that the refrigeration circuit that she/he was
about to access contained a flammable refrigerant, even if all warning
labels were somehow removed. This sleeve would be of the same red color
(PMS #185 or RAL 3020) and could also be boldly marked with a graphic
to indicate the refrigerant was flammable. The use of a colored plastic
sleeve or cap that is boldly marked with a graphic could be a cost-
effective alternative to painting or dyeing the service port, hose, or
pipe.

Charge Size Limitation

    Among the provisions in the UL Standard are limits on the amount of
refrigerant allowed in each appliance. The limitations on refrigerant
charge size for VLTR would be consistent with the UL Standard to reduce
the risk to workers and consumers. EPA is proposing to require a charge
size limit of 150 g for each refrigerant circuit or stage for the
proposed refrigerant. Section 1.1.1 of the UL Standard states, ``This
document details all the requirements when up to 150 g of FLAMMABLE
REFRIGERANT are used per stage of a REFRIGERATING SYSTEM. Additional
requirements beyond the current scope of this document apply if a
REFRIGERANT charge of FLAMMABLE REFRIGERANT exceeds this amount.''
Thus, in order to ensure the standard's provisions apply and
sufficiently address flammability risk, EPA is proposing that each
refrigerant circuit must contain no more than 150 g of R-1150.
    In addition to the general requirement that each refrigerant
circuit must contain no more than 150 g of R-1150, the UL Standard has
a requirement for the maximum charge for remote condensing unit using a
flammable refrigerant in Annex DD and Table DD.1. Section DD.2.4 of
Annex DD sets requirements for the minimum associated room area for a
given charge, based on a maximum refrigerant concentration of 0.38 lb/
1000 ft\3\, 5200 ppm, or 6 g/m\3\ for R-1150.
6. What narrowed use limits is EPA proposing?
    EPA is proposing the following narrowed use limits for use of R-
1150 in VLTR:
    (1) Temperature range--R-1150 may only be used in equipment
designed specifically to reach temperatures lower than -80 [deg]C (-112
[deg]F).
    (2) The manufacturers of new very low temperature equipment would
need to demonstrate that other alternatives are not technically
feasible. They must document the results of their evaluation that
showed the other alternatives to be not technically feasible and
maintain that documentation in their files. This documentation, which
does not need to be submitted to EPA unless requested to demonstrate
compliance, ``shall include descriptions of substitutes examined and
rejected, processes or products in which the substitute is needed,
reason for rejection of other alternatives, e.g., performance,
technical or safety standards, and the anticipated date other
substitutes will be available and projected time for switching to other
available substitutes.'' (40 CFR 82.180(b)(3)).
7. Why is EPA proposing these specific narrowed use limits?
    The boiling point (b.p.) of a refrigerant determines the coldest
temperature it can reach within its refrigerating capabilities. R-1150
has a b.p. of -104 [deg]C, allowing it to refrigerate as cold as -104
[deg]C. There are a limited number of refrigerants that are capable of
reaching temperatures below -80 [deg]C, such as the ODSs CFC-13 (b.p.,
-81.4 [deg]C) and R-503 (b.p., -88.9 [deg]C), and among the acceptable
refrigerants in this end-use, ethane (b.p., -88.3 [deg]C) and the high
GWP refrigerants HFC-23 (b.p., -84.4 [deg]C), R-508A (b.p., -87.4
[deg]C) and R-508B (b.p., -87.4 [deg]C).\38\ Given the limited
refrigerant options available for equipment designed to reach the sub -
80 [deg]C temperature range, EPA understands there is a need for
listing R-1150. However, EPA proposes that limiting the use of R-1150
to VLTR equipment designed to reach temperatures lower than -80 [deg]C
(-112 [deg]F) is necessary to mitigate local

air quality concerns discussed in section II.F.3 that could occur with
broad use, given the larger picture of VOC and generation of ground-
level ozone in areas like Los Angeles. If R-1150 were used broadly
across the refrigeration and AC sector, it could have significant
impacts on local air quality. For equipment in this end-use designed to
reach temperatures higher than -80 [deg]C (-112 [deg]F), other
alternatives with lower reactivities are widely available, e.g.,
CO2, ethane, propane, and R-410A. There are sufficient
refrigerant options available to fill the need in VLTR equipment
designed to reach temperatures higher than -80 [deg]C (-112 [deg]F)
without allowing the use of refrigerants as photochemically reactive as
R-1150.
---------------------------------------------------------------------------

    \38\ Engineering ToolBox, (2005). Refrigerants--Physical
Properties. Available online at: https://www.engineeringtoolbox.com/refrigerants-d_902.html Accessed October 28, 2021.
---------------------------------------------------------------------------

8. What additional information is EPA including in 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.E.2 above
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.
9. On which topics is EPA specifically requesting comment?
    EPA takes comment on this listing, including the proposed use
conditions and narrowed use limits. In particular, EPA takes comment on
the specific temperature range to which R-1150 should be limited. For
example, R-1150 could instead be listed as acceptable for equipment
designed to attain temperatures of -89 [deg]C (-128.2 [deg]F), lower
than the boiling point of ethane, since ethane could attain
temperatures down to -89 [deg]C and would present lower risk of
potential local air quality impacts because of lower reactivity in the
lower atmosphere than R-1150. EPA also takes comment on whether R-1150
should be listed as unacceptable, given the potential local air quality
impacts.

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

1. Background on Streaming and Total Flooding Fire Suppression
    The fire suppression and explosion protection end-uses addressed in
this action are total flooding and streaming. Total flooding systems,
which historically employed halon 1301 as a fire suppression agent, are
used in both normally occupied and unoccupied areas. In the United
States, approximately 90 percent of installed total flooding systems
protect anticipated hazards from ordinary combustibles (i.e., Class A
fires), while the remaining ten percent protect against applications
involving flammable liquids and gases (i.e., Class B fires).\39\ It is
also estimated that approximately 75 percent of total flooding systems
protect electronics (e.g., computers, telecommunications, process
control areas), while the remaining 25 percent protect other
applications, primarily in civil aviation (e.g., engine nacelles/
auxiliary power units, cargo compartments, lavatory trash receptacles),
military weapons systems (e.g., combat vehicles, machinery spaces on
ships, aircraft engines and tanks), oil/gas and manufacturing
industries (e.g., gas/oil pumping, compressor stations), and maritime
(e.g., machinery space, cargo pump rooms). Streaming applications,
which have historically used halon 1211 as an extinguishing agent,
include portable fire extinguishers designed to protect against
specific hazards.
---------------------------------------------------------------------------

    \39\ Wickham, 2002. Status of Industry Efforts to Replace Halon
Fire Extinguishing Agents. March 2002.
---------------------------------------------------------------------------

2. What is EPA's proposed listing decisions for 2-BTP?
    EPA is proposing to list 2-BTP as acceptable, subject to use
conditions, for use in normally unoccupied spaces under 500 ft\3\ in
total flooding fire suppression systems. In addition, EPA proposes to
list 2-BTP as acceptable, subject to use conditions, as a streaming
agent for use in non-residential applications, except for commercial
home office and personal watercraft. 2-BTP was previously listed as
acceptable, subject to use conditions, for use in engine nacelles and
auxiliary power units on aircraft in total flooding fire suppression
systems and for use in aircraft as a streaming agent (81 FR 86778,
December 1, 2016).
    The redacted submission and supporting documentation for 2-BTP are
provided in the docket for this proposed rule (EPA-HQ-OAR-2021-0836) at
https://www.regulations.gov. EPA performed assessments to examine the
health and environmental risks of this substitute during production
operations and the filling of fire extinguishers as well as in the case
of an inadvertent discharge of the system during maintenance activities
on the fire extinguishing system. These assessments are available in
the docket for this proposed rule.40 41
---------------------------------------------------------------------------

    \40\ ICF, 2022q. Risk Screen on Substitutes in Total Flooding
Systems in Normally Unoccupied Spaces. Substitute: 2-bromo-3,3,3-
trifluoropropene (2-BTP).
    \41\ ICF, 2022r. Risk Screen on Substitutes as Streaming Agents
in Non-Residential Applications. Substitute: 2-bromo-3,3,3-
trifluoropropene (2-BTP).
---------------------------------------------------------------------------

3. What is 2-BTP and how does it compare to other fire suppressants in
the same end-uses?
a. Total Flooding
    Environmental information: 2-BTP has an ODP of 0.0028 and a GWP of
0.23-0.26. The ODPs of other total flooding agents range from 0 to
0.048 and GWPs of other total flooding alternatives range from 0 to
3,500. 2-BTP is considered a VOC and is not excluded from EPA's
regulatory definition of VOC (see 40 CFR 51.100(s)) for the purpose of
addressing the development of SIPs to attain and maintain the NAAQS.
    Flammability information: 2-BTP is nonflammable.
    Toxicity and exposure data: EPA assessed potential health risks
from exposure to the proposed substitute as a total flooding agent in
normally unoccupied spaces up to 14.2 m\3\ (500 ft\3\) during
manufacture, installation, and servicing, consistent with the use
description provided by the submitter. According to the SDS, exposure
to 2-BTP following a discharge may be hazardous if inhalation, skin
contact, or eye contact with the proposed substitute occurs at
sufficiently high levels. However, the most likely pathway of exposure
is through inhalation, which may cause central nervous system effects,
such as dizziness, confusion, physical incoordination, drowsiness,
anesthesia, or unconsciousness. The cardiotoxic Lowest Observed Adverse
Effect Level (LOAEL) for this agent is 1.0 percent (10,000 ppm), at
which level exposure may cause increased sensitivity of the heart to
adrenaline, which might cause irregular heartbeats

and possibly ventricular fibrillation or death.
    2-BTP vapors may reduce oxygen available for breathing, causing
asphyxiation in high concentrations. Such vapors pose a potential
hazard if large volumes are trapped in enclosed or low places. In
addition, as noted above, if person(s) are exposed to high
concentrations, the person(s) may experience central nervous system
effects, such as drowsiness and dizziness, which may result in the
person(s) not realizing that he/she is suffocating. These health
effects after exposure are similar for other common fire suppressants.
    To assess potential health risks from exposure to the proposed
substitute for personnel during manufacturing, EPA developed an AEL of
2 ppm for 2-BTP based on review of available toxicity studies.\42\ The
AEL represents the maximum 8-hour TWA at which personnel in an
occupational environment can be exposed regularly without adverse
effects. The estimated exposure values provided by the submitter are
greater than the occupational AEL. To effectively mitigate potential
occupational exposure and maintain average exposure levels below the
occupational AEL of 2 ppm, the manufacturing space should be equipped
with specialized engineering controls and well ventilated with a local
exhaust system and low-lying source ventilation. The sampling data
provided by the submitter demonstrate that local exhaust ventilation
greatly reduces exposure concentration inside the fill booth and in the
filling area.
---------------------------------------------------------------------------

    \42\ ICF, 2022q. Risk Screen on Substitutes in Total Flooding
Systems in Normally Unoccupied Spaces. Substitute: 2-bromo-3,3,3-
trifluoropropene (2-BTP).
---------------------------------------------------------------------------

    Exposure to the proposed substitute is not likely during
installation or servicing of 2-BTP total flooding systems for normally
unoccupied spaces. The risk of accidental activation of the fire
extinguishing system while personnel are present near the protected
space is highly unlikely if proper procedures are followed. Proper
instructions on system installation and servicing included in manuals
for the 2-BTP systems should be adhered to. In the case of accidental
release, required engineering controls in accordance with the National
Fire Protection Association (NFPA) 2001 Standard on Clean Agent Fire
Extinguishing Systems to limit personnel exposure to discharges should
be employed with 2-BTP systems.
    EPA provides additional information on safe use of this substitute
for establishments manufacturing, installing and maintaining equipment
using this agent in the ``Further Information'' column of the
regulatory listing. EPA recommends that a time delay of 30 to 60
seconds is programmed in accordance with the NFPA 2001 standard.
Although exposure is highly unlikely during installation and
maintenance activities, exposure is possible upon reentry into a space
after a system has been discharged. In the event of an accidental
release, the space should be adequately ventilated. EPA recommends that
personnel wear protective clothing, goggles, gloves, and particulate-
removing respirators with National Institute for Occupational Safety
and Health (NIOSH) type N95 or better filters while performing
installation or maintenance, and a self-contained breathing apparatus
(SCBA) while performing clean-up activities to reduce the risk of
exposure. Since this additional information is not part of the
regulatory decision under SNAP, these statements are not binding for
use of the substitute under the SNAP program. While the items listed
are not legally binding under the SNAP program, EPA encourages users of
substitutes to apply all statements in the ``Further Information''
column in their use of this substitute.
    2-BTP is not expected to cause a significant risk to human health
in the general population when used in total flooding systems in
normally unoccupied areas. The proposed use in spaces under 500 ft\3\
would require a smaller amount of fire suppressant, reducing potential
exposures to workers and the general public and reducing potential
toxicity risks. Disposal of 2-BTP total flooding systems is subject to
local, state, and federal regulations, which ensure that 2-BTP and
water contaminated with 2-BTP are not to be dumped into sewers, on the
ground, or into any body of water, but rather taken to a wastewater
treatment facility or disposed of properly. 2-BTP is not considered to
be hazardous waste under EPA regulations implementing RCRA at 40 CFR
part 261. EPA provides additional information on safe use of this
substitute for establishments manufacturing, installing and maintaining
equipment using this agent in the ``Further Information'' column of the
proposed regulatory listing. Since this additional information is not
part of the regulatory decision under SNAP, these statements are not
binding for use of the substitute under the SNAP program. While the
items listed are not legally binding under the SNAP program, EPA
encourages users of substitutes to apply all statements in the
``Further Information'' column in their use of this substitute.
    Comparison to other fire suppressants: 2-BTP has an ODP of 0.0028,
comparable to or lower than other listed substitutes in this end-use,
with ODPs ranging from zero to 0.048. 2-BTP has a GWP of 0.23-0.26 that
is lower than or comparable to that of other acceptable substitutes for
total flooding agents, with GWPs that range from about zero to 3,500.
2-BTP is considered a VOC and is not excluded from EPA's regulatory
definition of VOC (see 40 CFR 51.100(s)) addressing the development of
SIPs to attain and maintain the NAAQS. Other acceptable fire
suppression agents currently in use in this end-use are also VOC (e.g.,
C6-perfluoroketone), and 2-BTP is anticipated to pose no
greater risk than other alternatives listed as acceptable in this end-
use. Emissions of 2-BTP should be controlled by adhering to standard
industry practices. Toxicity risks can be minimized by use consistent
with the NFPA 2001 standard, recommendations in the SDS, and other
safety precautions common in the fire suppression industry. The
potential toxicity risks due to inhalation exposure are common to many
total flooding agents, including those already listed as acceptable
under SNAP for this same end-use. 2-BTP post-activation products are
nonflammable, as are all other available total flooding agents.
    EPA is proposing to find 2-BTP acceptable, subject to use
conditions, as a total flooding agent for use in normally unoccupied
spaces under 500 ft\3\ because the overall environmental and human
health risk posed by the substitute is lower than or comparable to the
overall risk posed by other alternatives listed as acceptable in the
same end-use.
b. Streaming Uses
    Environmental information: The environmental information for this
substitute is set forth in the ``Environmental information'' section in
listing II.G.3.a above.
    Flammability information: 2-BTP is nonflammable.
    Toxicity and exposure data: Toxicity and personal protective
equipment (PPE) information is described above under total flooding
applications. EPA evaluated occupational and general population
exposure at manufacture and at end-use to ensure that the use of 2-BTP
as a streaming agent will not pose unacceptable risks to workers or the
general public. For the occupational exposure assessment, EPA has
evaluated

the risks associated with potential exposures to 2-BTP during
production operations and the filling of fire extinguishers as well as
in the case of an inadvertent discharge of the fire extinguisher during
maintenance activities.
    2-BTP is not expected to pose a risk to workers during manufacture
when the engineering controls and PPE requirements as referenced in the
SDS for this proposed substitute are followed. The potential health
risks from exposure to the proposed substitute for personnel during
manufacturing is described above under total flooding applications.
    EPA also assessed potential end-use exposure scenario at 7.5-minute
and 15-minute TWA exposures for 2-BTP following potential release of
agent from the handheld extinguisher in confined spaces (e.g.,
electronics and server rooms).\43\ These exposures were then compared
with the cardiotoxic LOAEL for 2-BTP. All but one modeled 7.5-minute
and 15-minute exposures for varying ventilation rates were lower than
the LOAEL of 10,000 ppm for 2-BTP. The estimated exposures were derived
using conservative assumptions (i.e., no mechanical ventilation) and
represent a worst-case scenario with a low probability of occurrence.
Because anticipated exposures could exceed the exposure limit for 2-
BTP, EPA recommends that standard safety techniques to ensure safety
during the use of 2-BTP fire extinguishers be followed in non-
residential locations. 2-BTP handheld extinguishers must follow
required minimum room volumes established by UL 2129, Halocarbon Clean
Agent Fire Extinguishers,\44\ when discharged into a confined space.
This standard prohibits the exceedance of the cardiotoxic LOAEL for any
fire suppressant (i.e., 10,000 ppm or 1.0% for 2-BTP). Therefore, per
UL 2129, a warning label for 2-BTP extinguishers will mitigate use in
confined spaces. Based on the above results, 2-BTP is not expected to
pose significant risk to end users when used as a streaming fire
extinguishing agent in non-residential applications, except for
commercial home office and personal watercraft. EPA provides additional
information on safe use of this substitute for establishments
manufacturing, installing and maintaining equipment using this agent in
the ``Further Information'' column of the regulatory listing. Since
this additional information is not part of the regulatory decision
under SNAP, these statements are not binding for use of the substitute
under the SNAP program. While the items listed are not legally binding
under the SNAP program, EPA encourages users of substitutes to apply
all statements in the ``Further Information'' column in their use of
this substitute.
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    \43\ ICF, 2022r. Risk Screen on Substitutes as Streaming Agents
in Non-Residential Applications. Substitute: 2-bromo-3,3,3-
trifluoropropene (2-BTP).
    \44\ UL, 2017. Standard 2129--Halocarbon Clean Agent Fire
Extinguishers. Edition 3. This document is accessible at: https://www.shopulstandards.com/ProductDetail.aspx?UniqueKey=32182.
---------------------------------------------------------------------------

    Comparison to other fire suppressants: 2-BTP has an ODP of 0.0028,
comparable to other listed substitutes in this end-use, with ODPs
ranging from zero to 0.022. 2-BTP has a GWP of 0.23-0.26, which for
streaming agents is lower than or comparable to that of other
acceptable substitutes, with GWPs that range from about zero to 3,220.
2-BTP is considered a VOC and is not excluded from EPA's regulatory
definition of VOC (see 40 CFR 51.100(s)) addressing the development of
SIPs to attain and maintain the NAAQS. Other acceptable fire
suppression agents currently in use in this end-use are also VOC (e.g.,
C6-perfluoroketone), and 2-BTP is anticipated to pose no
greater risk than other alternatives listed as acceptable in this end-
use. Toxicity risks can be minimized by use consistent with the NFPA 10
Standard for Portable Fire Extinguishers, recommendations in the SDS,
and other safety precautions common in the fire suppression industry.
    EPA is proposing to find 2-BTP as acceptable, subject to use
conditions, as a streaming agent for use in non-residential
applications, except for commercial home office and personal
watercraft, because the overall environmental and human health risk
posed by the substitute is lower than or comparable to the overall risk
posed by other alternatives listed as acceptable in the same end-use.
4. What use conditions is EPA proposing?
    EPA is proposing to list 2-BTP as acceptable, subject to use
conditions, for use in normally unoccupied spaces under 500 ft\3\ in
total flooding fire suppression systems, and as acceptable, subject to
use conditions, as a streaming agent for use in non-residential
applications, except for commercial home offices and personal
watercrafts.
5. Why is EPA proposing these specific use conditions?
    EPA is proposing to list 2-BTP as acceptable, subject to use
conditions, for use in normally unoccupied spaces under 500 ft\3\ in
total flooding fire suppression systems. These limitations are
consistent with additional information submitted to EPA. The
limitations correspond to use in small enclosed spaces, such as an
electrical closet. Such spaces would require a smaller amount of fire
suppressant, reducing potential exposures to workers and the general
public and reducing potential toxicity risks.
    Additionally, EPA is proposing to list 2-BTP as acceptable subject
to use conditions as a streaming agent for use in non-residential
applications, except for commercial home office and personal
watercrafts. The definition of ``residential use'' in the SNAP
regulations at 40 CFR 82.172 is use by a private individual of a
chemical substance or any product containing the chemical substance in
or around a permanent or temporary household, during recreation, or for
any personal use or enjoyment. Use within a household for commercial or
medical applications is not included in this definition, nor is use in
automobiles, watercraft, or aircraft. Use in a commercial home office
or in personal watercraft could result in exposure to members of the
general public, including sensitive individuals such as children or the
elderly. In addition, air exchange is often lower in a home office or a
personal watercraft than in industrial or other commercial
applications, potentially resulting in higher exposure levels than in
those other non-residential applications. Because of the more sensitive
populations and potentially higher exposures associated with those
applications, EPA is proposing to list 2-BTP for use in non-residential
applications other than commercial home office and personal watercraft.
6. On which topics is EPA specifically requesting comment?
    EPA is requesting comment on all aspects of the proposed listing
decision, including the proposed use conditions.

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

1. What is EPA's proposed listing decision for EXXFIRE[supreg]?
    EPA is proposing to list EXXFIRE[supreg] as acceptable, subject to
use conditions, for use in total flooding fire suppression systems in
normally unoccupied spaces. Prior to activation, the EXXFIRE[supreg]
formulation is in solid form and contained within a hermetically sealed
steel container. Upon detection of a fire, nitrogen gas is released
from the unit.

The nitrogen gas dilutes the oxygen level within the enclosure, and
consequently suppresses the fire. After activation, only gas components
exit the casing. All solid products remain inside the casing before,
during and after activation. Use of this agent should be in accordance
with the safety guidelines in the latest edition of the NFPA 2001
standard.
    The redacted submission and supporting documentation for
EXXFIRE[supreg] are provided in the docket for this proposed rule (EPA-
HQ-OAR-2021-0836) at https://www.regulations.gov. EPA performed an
assessment to examine the health and environmental risks of each of
this substitute. This assessment is available in the docket for this
proposed rule.\45\
---------------------------------------------------------------------------

    \45\ ICF, 2022s. Risk Screen on Substitutes in Total Flooding
Systems in Normally Unoccupied Spaces; Substitute: EXXFIRE[supreg].
---------------------------------------------------------------------------

2. What is EXXFIRE[supreg] and how does it compare to other fire
suppressants in the same end-use?
    Environmental information: According to the submitter, the active
ingredients for this technology are nonvolatile solids before
activation so the ODP, atmospheric lifetime, and GWP are all zero. The
gaseous post-activation products that are released upon activation of
the fire suppressant with GWPs are carbon monoxide (CO),
CO2, and various hydrocarbons with GWPs ranging from less
than one to 25; however, these compounds are present in trace amounts,
together making up less than 0.5 percent of the total weight of the
post-activation products. The majority of the post-activation
constituents of EXXFIRE[supreg] are either not organic (e.g., nitrogen,
oxygen, water, hydrogen) or are excluded from EPA's regulatory
definition of VOC (see 40 CFR 51.100(s)), addressing the development of
SIPs to attain and maintain the NAAQS. Some constituents of
EXXFIRE[supreg] are considered VOC and are not excluded from EPA's
regulatory definition of VOC (see 40 CFR 51.100(s)), including a
variety of hydrocarbons; however, these compounds are present in trace
amounts.
    Flammability information: EXXFIRE[supreg] post-activation products
are nonflammable, except for certain hydrocarbons that are present in
trace amounts.
    Toxicity and exposure data: EPA assessed potential health risks
from exposure . . . . Most post-activation products for EXXFIRE[supreg]
are not expected to result in adverse health effects; however, due to
the potential presence of lithium fluoride, which is acutely toxic upon
inhalation or ingestion and can cause serious skin, eye, and
respiratory tract irritation, the use of this system is only
recommended for use in normally unoccupied spaces. Although expected to
be maintained inside the generator, the potential presence of lithium
fluoride in the post-activation particulate products justifies the
necessity for personnel to wear proper PPE (i.e., particulate-removing
respirator with NIOSH type N95 or better filters) upon reentry into the
space following a discharge of the system to mitigate those risks. The
submitter indicates that the proposed substitute can reduce oxygen
levels to 10 to 12 percent, which can cause a potential asphyxiation
hazard.
    EPA evaluated occupational and general population exposure at
manufacture and at end use to ensure that the use of EXXFIRE[supreg]
will not pose unacceptable risks to workers or the general public.
Exposure is possible upon reentry into a space after a system has been
discharged. Protective gloves, tightly sealed goggles, protective work
clothing, and particulate-removing respirators should be worn for
installation and servicing activities, to protect workers in any event
of potential discharge of the proposed substitute, accidental or
otherwise. Filling or servicing operations should be performed in well-
ventilated areas. Toxicity risks can be minimized by use consistent
with the NFPA 2001 standard, recommendations in the SDS, and other
safety precautions common in the fire suppression industry. EPA
provides additional information on safe use of this substitute for
establishments manufacturing, installing and maintaining equipment
using this agent in the ``Further Information'' column of the
regulatory listing. Since this additional information is not part of
the regulatory decision under SNAP, these statements are not binding
for use of the substitute under the SNAP program. While the items
listed are not legally binding under the SNAP program, EPA encourages
users of substitutes to apply all statements in the ``Further
Information'' column in their use of this substitute.
    Comparison to other fire suppressants: EXXFIRE[supreg] has an ODP
of zero, comparable to other listed substitutes in this end-use, with
ODPs ranging from zero to 0.048. For total flooding agents,
EXXFIRE[supreg] has a GWP of zero prior to activation (and one to 25
for certain post-activation products present in trace amounts), which
is comparable to or lower than that of other acceptable substitutes,
such as HFC-227ea and other HFCs, with GWPs up to 3,500. The majority,
approximately 99.5 percent, of the post-activation constituents of
EXXFIRE[supreg] are either not organic or are excluded from EPA's
regulatory definition of VOC (see 40 CFR 51.100(s)), addressing the
development of SIPs to attain and maintain the NAAQS. EXXFIRE[supreg]
is anticipated to pose no greater risk than other alternatives listed
as acceptable in this end-use. Toxicity risks can be minimized by use
consistent with the NFPA 2001 standard, recommendations in the SDS, and
other safety precautions common in the fire suppression industry. The
potential toxicity risks due to inhalation exposure are common to many
total flooding agents, including those already listed as acceptable
under SNAP for this same end-use. EXXFIRE[supreg]'s post-activation
products are nonflammable, as are all other available total flooding
agents.
    EPA is proposing to list EXXFIRE[supreg] as acceptable, subject to
use conditions, in the end-use listed above because it does not pose
greater overall environmental and human health risk than other
available substitutes in the same end-use.
3. What use conditions is EPA proposing and why?
    Consistent with the request by the submitter, the use condition
requires that EXXFIRE[supreg] be used in total flooding fire
suppression systems only in areas that are not normally occupied. EPA
conducted this evaluation for use only in unoccupied spaces, and
information was provided by the submitter in the SNAP application
specific for this type of space based on EPA guidance.\46\
---------------------------------------------------------------------------

    \46\ EPA, 2004. A Guide to Completing a Risk Screen: Collection
and Use of Risk Screen Data. Fire Suppression Sector. April 2004.
---------------------------------------------------------------------------

4. On which topics is EPA specifically requesting comment?
    EPA is requesting comment on all aspects of the proposed listing
decision, including the proposed use conditions.

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

1. What is EPA's proposed listing decision for Powdered Aerosol H?
    EPA is proposing to list Powdered Aerosol H, also known as
Pyroquench-[alpha]TM, as acceptable, subject to use
conditions, for use in total flooding fire suppression systems in
normally unoccupied spaces. Prior to activation, the Powdered Aerosol H
formulation is

contained as a solid disk of chemicals in insulated and dual-sealed
casings. In response to heat and lack of oxygen, the formulation
undergoes a chemical reaction; once the Powdered Aerosol H system is
activated, it generates and discharges a homogenous mixture of gas and
particulates into a space containing a fire hazard or directly on the
hazard itself, extinguishing the fire. In the ``Further Information''
column of the tables at the end of this document, we state that use of
this agent should be in accordance with the safety guidelines in the
latest edition of the NFPA 2010 Standard for Fixed Aerosol Fire
Extinguishing Systems.
    The redacted submission and supporting documentation for Powdered
Aerosol H are provided in the docket for this proposed rule (EPA-HQ-
OAR-2021-0836) at https://www.regulations.gov. EPA performed an
assessment to examine the health and environmental risks of each of
this substitute. This assessment is available in the docket for this
proposed rule.\47\
---------------------------------------------------------------------------

    \47\ ICF, 2022t. Risk Screen on Substitutes in Total Flooding
Systems in Normally Unoccupied Spaces; Substitute: Pyroquench-
[alpha]TM.
---------------------------------------------------------------------------

2. What is Powdered Aerosol H and how does it compare to other fire
suppressants in the same end-use?
    Environmental information: According to the submitter, the active
ingredients for this technology are nonvolatile solids before
activation so the ODP, atmospheric lifetime, and GWP are all zero. The
gaseous post-activation products that are released upon activation of
the fire suppressant with GWPs are nitrogen dioxide (NO2)
and CO2, with GWPs of 120 and one, respectively. The post-
activation constituents of Powdered Aerosol H are excluded from EPA's
regulatory definition of VOC (see 40 CFR 51.100(s)), addressing the
development of SIPs to attain and maintain the NAAQS.
    Flammability information: Powdered Aerosol H post-activation
products are nonflammable.
    Toxicity and exposure data: EPA assessed potential health risks
from exposure to the proposed substitute as a total flooding agent in
normally unoccupied spaces. Because the pre-activation components of
the fire suppressant are prepared in tablets that are non-reactive and
do not crumble or flake, there is no concern with regard to inhalation
or ingestion of the pre-activation compounds. The discharge of the
powdered aerosol after activation results in temporary reduced
visibility in the protected space due to the uniform distribution of
the particulate generated and may cause ocular, dermal, and respiratory
irritation. EPA recommends that workers should not enter the space
following discharge until all particles have settled and the gases
released by the total flooding system have dissipated. Use according to
the NFPA 2010 Standard will reduce any safety risks due to reduced
visibility. The use of proper PPE, such as protective clothing, gloves,
goggles, and particulate-removing respirators, during manufacturing, at
installation, maintenance, and clean-up, minimizes personnel exposure
from inhalation of the substitute. EPA provides additional information
on safe use of this substitute for establishments manufacturing,
installing and maintaining equipment using this agent in the ``Further
Information'' column of the regulatory listing. Since this additional
information is not part of the regulatory decision under SNAP, these
statements are not binding for use of the substitute under the SNAP
program. While the items listed are not legally binding under the SNAP
program, EPA encourages users of substitutes to apply all statements in
the ``Further Information'' column in their use of this substitute.
    EPA expects that procedures identified in the SDS for Powdered
Aerosol H and good manufacturing practices will be adhered to, and that
the appropriate safety and personal PPE consistent with OSHA guidelines
will be used during installation, servicing, post-discharge clean-up
and disposal of total flooding systems using Powdered Aerosol H. The
manufacturer guidance upon installation of the system provides the
appropriate time after which workers may re-enter the area for disposal
to allow the maximum settling of all particulates.
    Comparison to other fire suppressants: The post-activation products
of Powdered Aerosol H have an ODP of zero, comparable to or lower than
other listed substitutes in this end-use, with ODPs ranging from zero
to 0.048. For total flooding agents, Powdered Aerosol H's GWP of zero
prior to activation (and one to 120 for certain post-activation
products) is comparable to or lower than that of other acceptable
substitutes, such as HFC-227ea and other HFCs, with GWPs up to 3,500.
Other acceptable substitutes in this end-use have comparable GWPs
ranging from zero to one, such as water, inert gases, and other
powdered aerosol fire suppressants. Toxicity risks can be minimized by
use consistent with the NFPA 2010 standard, recommendations in the SDS,
and other safety precautions common in the fire suppression industry.
The potential toxicity risks due to inhalation exposure are common to
many total flooding agents, including those already listed as
acceptable under SNAP for this same end-use. Powdered Aerosol H's post-
activation products are nonflammable, as are all other available total
flooding agents.
    EPA is proposing to list Powdered Aerosol H as acceptable, subject
to use conditions, in the end-use listed above because it does not pose
greater overall environmental and human health risk than other
available substitutes in the same end-use.
3. What use conditions is EPA proposing and why?
    Consistent with the submitter's request, EPA proposes the use
condition that Powdered Aerosol H be used in total flooding fire
suppression systems only in areas that are not normally occupied. EPA
conducted this evaluation for use only in unoccupied spaces, and
information was provided by the submitter in the SNAP application
specific for this type of space based on EPA guidance.\48\
---------------------------------------------------------------------------

    \48\ EPA, 2004. A Guide to Completing a Risk Screen: Collection
and Use of Risk Screen Data. Fire Suppression Sector. April, 2004.
---------------------------------------------------------------------------

4. On which topics is EPA specifically requesting comment?
    EPA is requesting comment on all aspects of the proposed listing
decision, including the proposed use conditions.

III. Request for Advance Comment on Potential Approaches to SNAP
Listing Decisions for Certain Very Short-Lived Substances

    In making decisions regarding whether a substitute is acceptable or
unacceptable, and whether substitutes present risks that are lower than
or comparable to risks from other substitutes that are currently or
potentially available in the end-uses under consideration, EPA examines
the criteria in 40 CFR 82.180(a)(7) which includes (i) atmospheric
effects and related health and environmental impacts; (ii) general
population risks from ambient exposure to compounds with direct
toxicity and to increased ground-level ozone; (iii) ecosystem risks;
(iv) occupational risks; (v) consumer risks; (vi) flammability; and
(vii) cost and availability of the substitute. The ability of a
chemical to destroy ozone is represented quantitatively by its ODP,
which is the ratio of the amount of ozone that would be destroyed by
the emission of a given mass of that chemical to the amount of

ozone destroyed by emission of the same mass of CFC-11. In order for a
chemical to deplete stratospheric ozone, it must be transported from
the troposphere, where almost all emissions occur, to the stratosphere,
where release of its halogen atoms can trigger catalytic ozone
destruction.
    Most class I and class II ODS are fairly stable in the troposphere
and persist long enough to become well-mixed in the troposphere and
then be transported into the stratosphere. Because of their longer
tropospheric lifetimes and tropospheric mixing, the ability of these
chemicals to deplete stratospheric ozone depends little on where on the
surface of the Earth or during which season the chemicals are released,
and so the ability of a particular chemical to destroy ozone can
reasonably be represented by a single ODP value that is constant over
space and time. However, some alternatives that contain chlorine,
bromine, and/or iodine are more reactive and have shorter atmospheric
lifetimes. Halogenated substances with atmospheric lifetimes shorter
than about six months are called very short-lived substances (VSLS).
Given the shorter atmospheric lifetimes of VSLS, the location of
emissions can significantly impact the amount of ozone depletion that
results. Emissions at locations where atmospheric conditions quickly
move VSLS to the stratosphere will result in more ozone depletion.
Conversely, emissions from locations where atmospheric conditions
result in VSLS moving more slowly to the stratosphere result in less
ozone depletion. If there are different ODPs calculated for different
regions, the reported consensus value in WMO (2018) is the upper limit
of those values. While not the only source of information used by the
Agency, EPA regards the quadrennial report of the Montreal Protocol's
Scientific Assessment Panel as the premier source for information
concerning stratospheric ozone science. Appendix A of the Scientific
Assessment of Ozone Depletion: 2018 (WMO, 2018) contains a compilation
of metrics, including ODPs, for ODS, ODS alternatives, and related
species, based on best available data. The international scientific
community considers these ODPs to be consensus ODPs.
    Given the United States is a party to the Montreal Protocol with
196 other countries, we recognize the importance of a globally
consistent approach to considering ODPs. A globally consistent approach
to assessing risk of alternatives is also important because SNAP
listing decisions are often used by other countries as a signal that
the alternative is safe. Thus, considerations under the SNAP program
about the ozone depletion risk of a particular chemical have been based
on an ODP that is the consensus of the scientific community.
    Under the SNAP program EPA has found alternatives with ODPs to be
unacceptable. However, having a non-zero ODP does not necessarily make
a substance unacceptable in all contexts. We have previously listed
alternatives with an ODP, including listing class II substances as
alternatives to class I substances--noting that many of those class II
substances have subsequently been listed as unacceptable and were also
listed as chemicals to be phased out under the Montreal Protocol and
the Clean Air Act. We have also listed alternatives with an ODP as
acceptable, subject to use restrictions. In a few cases, particularly
where the ODP is several orders of magnitude below that of the class II
substances, we have listed the alternative as acceptable without any
use restrictions. In other words, a substitute with a measurable ODP
could be determined to reduce overall risks to human health and the
environment, compared with other currently or potentially available
alternatives. For example, the SNAP program listed a number of class II
ODS as acceptable as substitutes to class I ODS and changed the status
to unacceptable when alternatives with lower ODPs became available.
    The SNAP program has made some acceptability determinations
regarding VSLS in the past. Two examples are given below:
     In 1995, EPA listed the VSLS trifluoroiodomethane
(CF3I) as acceptable with use restrictions for specialized
total flooding fire suppression applications, noting that its ODP was
then estimated to be 0.008-0.01, lower than some class II ODS listed as
acceptable fire suppressants in the same end-use at that time.\49\
Given the limited applications where this chemical was found to be
acceptable, it has not been widely used. More recent studies have found
CF3I emissions in different regions have an ODP ranging from
0.0034 (Europe) to 0.094 (S. Asia).50 51 These studies were
considered by WMO in their 2018 report, which lists an ODP of <0.09 for
CF3I.
---------------------------------------------------------------------------

    \49\ 60 FR 31092, June 13, 1995.
    \50\ Brioude et al. (2010). Variations in ozone depletion
potentials of very short-lived substances with season and emission
region, Geophys. Res. Lett., 37, L19804, doi:10.1029/2010GL044856,
2010.
    \51\ Youn et al. (2010). Potential impact of iodinated
replacement compounds CF3I and CH3I on
atmospheric ozone: A three-dimensional modeling study, Atmos. Chem.
Phys., 10, 10,129-10,144,doi:10.5194/acp-10-10129-2010, 2010.
---------------------------------------------------------------------------

     In 2012, SNAP listed HCFO-1233zd(E), a VSLS with a WMO-
listed ODP of <0.0004 (WMO, 2018), as acceptable for use as a blowing
agent in polyurethane foams (77 FR 47768; August 10, 2012). This VSLS
has an ODP orders of magnitude below the class II substances it can
replace and has become more widely used in part because of its very low
ODP and GWP.
    EPA's SNAP program has received a submission to find the blend R-
466A acceptable in certain end uses in the refrigeration and AC sector.
This blend contains CF3I, which is listed by the World
Meteorological Organization (WMO, 2018) as having an ODP of < 0.09.
This is significantly higher than the ODPs of some HCFCs subject to
phaseout, e.g., HCFC-22 has an ODP of 0.055 and HCFC-123 has an ODP of
0.02.\52\ While EPA has at times listed substitutes that have non-zero
ODPs, including VSLS, as acceptable under the SNAP program, EPA has
also at times listed substitutes with ODPs as unacceptable. While EPA
is not proposing any action on the substitute R-466A in this proposal,
we note that broad use of R-466A, containing CF3I, for air
conditioning end-uses could lead to large amounts of emissions on an
ODP-weighted basis. If R-466A were to penetrate the AC market to the
extent that it substituted for 10 percent of the R-410A estimated to be
used annually in the United States in 2022, this would mean consumption
of over 200 ODP-weighted tons using the consensus ODP values of 0.09
for CF3I and 0.036 for R-466A. For comparison, the U.S. cap
on HCFC consumption is currently 75 ODP-weighted tons annually. While
HCFO-1233zd(E) is also a VSLS with potential for widespread use, the
WMO-listed ODP of <0.0004 for HCFO-1233zd(E) is two orders of magnitude
less than that of CF3I and EPA's Vintaging Model estimates
annual U.S. consumption at less than 5 ODP-weighted tons.
---------------------------------------------------------------------------

    \52\ N.B. There are limitations on the use of HCFC-123 as
detailed in section II.A.3 above.
---------------------------------------------------------------------------

    The Agency is seeking advance comment on how EPA should address
VSLS within the SNAP program to inform potential future listing
decisions. EPA is specifically requesting comment on the following
questions:
     Should EPA consider finding a VSLS with a WMO-listed ODP
that is similar to the ODP of substances that have been phased out
under the CAA Title VI to be unacceptable under SNAP?

     Should EPA take a more conservative approach when
determining whether VSLS with ODPs similar to class II substances are
acceptable alternatives under SNAP given these substances are not
listed as class II substances under the CAA and therefore are not
scheduled to be phased out?
     How should the Agency consider submissions of VSLS with
ODPs similar to class II ODS, or blends containing such VSLS, as
alternatives in light of the reality that SNAP listings are used by
other countries to determine whether an alternative may be acceptable?

IV. 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 action does not impose an information collection
burden under the PRA.

C. Regulatory Flexibility Act (RFA)

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

D. Unfunded Mandates Reform Act (UMRA)

    This action does not contain any unfunded mandate as described in
UMRA, 2 U.S.C. 1531-1538, and does not significantly or uniquely affect
small governments. The action imposes no enforceable duty on any state,
local or tribal governments or the private sector.

E. Executive Order 13132: Federalism

    This action does not have federalism implications. It will not have
substantial direct effects on the states, on the relationship between
the national government and the states, or on the distribution of power
and responsibilities among the various levels of government.

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

    This action does not have tribal implications as specified in
Executive Order 13175. It will not have substantial direct effects on
tribal governments, on the relationship between the Federal government
and Indian tribes, or on the distribution of power and responsibilities
between the Federal government and Indian tribes, as specified in
Executive Order 13175. Thus, Executive Order 13175 does not apply to
this action. EPA periodically updates tribal officials on air
regulations through the monthly meetings of the National Tribal Air
Association and will share information on this rulemaking through this
and other fora.

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

    This action is not subject to Executive Order 13045 because the
rule is not economically significant as defined in Executive Order
12866, and because EPA does not believe the environmental health or
safety risks addressed by this action present a disproportionate risk
to children. While EPA has not conducted a separate analysis of risks
to infants and children associated with this rule, the rule does
contain use conditions that would reduce exposure risks to the general
population, with the reduction of exposure being most important to the
most sensitive individuals. This action's health and risk assessments
are contained in the comparisons of toxicity for the various
substitutes, as well as in the risk screens for the substitutes that
are listed in this proposed rule. The risk screens are in the docket
for this rulemaking.

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

    This action is not subject to Executive Order 13211, because it is
not a significant regulatory action under Executive Order 12866.

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

    This action involves technical standards. EPA uses and incorporates
by reference portions of the 2019 UL Standard 60335-2-40, which
establishes requirements for the evaluation of residential AC equipment
and safe use of flammable refrigerants, among other things.
Additionally, EPA uses and incorporates by reference portions of the
2021 UL Standard 61010-2-011, which establishes requirements for the
evaluation of

laboratory equipment. These standards are discussed in greater detail
in sections II.D.1 and II.E.4 of this preamble.
    The 2019 UL Standard 60335-2-40 and 2021 UL Standard 61010-2-011
are available at http://www.shopulstandards.com/ProductDetail.aspx?UniqueKey=36463 and may be purchased by mail at:
COMM 2000, 151 Eastern Avenue, Bensenville, IL 60106; email:
[email protected]; Telephone: 1-888-853-3503 in the U.S. or
Canada (other countries dial 1-415-352-2178); internet address: http://ulstandards.ul.com/ or www.comm-2000.com. The cost of each of the 2019
UL Standard 60335-2-40 and 2021 UL Standard 61010-2-011 is $440 for an
electronic copy and $550 for hard copy. UL also offers a subscription
service to the Standards Certification Customer Library that allows
unlimited access to their standards and related documents. The cost of
obtaining this standard is not a significant financial burden for
equipment manufacturers and purchase is not necessary for those
selling, installing, and servicing the equipment. Therefore, EPA
concludes that the UL standard incorporated by reference is reasonably
available.
    EPA is also incorporating by reference ANSI/ASHRAE Standard 15-
2019, Safety Standard for Refrigeration Systems, in the use conditions
for six refrigerants listed for use in chillers. This standard is
available at https://www.ashrae.org/resources-publications/bookstore/standards-15-34 and may be purchased by mail at: 6300 Interfirst Drive,
Ann Arbor, MI 48108; by telephone: 1-800-527-4723 in the U.S. or
Canada; internet address: http://www.techstreet.com/ashrae/ashrae_standards.html?ashrae_auth_token=. The cost of ASHRAE Standard
15-2019 is $159.00 for an electronic copy or hard copy. The cost of
obtaining this standard is not a significant financial burden for
equipment manufacturers or for those selling, installing and servicing
the equipment. Therefore, EPA concludes that the ASHRAE standard
proposed to be incorporated by reference is reasonably available.
    EPA has already incorporated the following standards into appendix
R: UL 471 (November 24, 2010); UL 484 (December 21, 2007, with changes
through August 3, 2012).; UL 541 (December 30, 2011); and UL 60335-2-24
(April 28, 2017).

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

    A regulatory action may involve potential environmental justice
concerns if it could: (1) Create new disproportionate impacts on people
of color, communities of low-income, and/or indigenous peoples; (2)
exacerbate existing disproportionate impacts on people of color,
communities of low-income, and/or indigenous peoples; or (3) present
opportunities to address existing disproportionate impacts on people of
color, communities of low-income, and/or indigenous peoples through the
action under development.
    EPA believes that this action does not create disproportionately
high and adverse human health or environmental effects on people of
color, communities of low-income and/or indigenous peoples, as
specified in Executive Order 12898 (59 FR 7629, February 16, 1994) and
may help reduce any existing disproportionate impacts. The proposed
listings for HFC-32, HFO-1234yf, R-452B, R-454A, R-454B, R-454C, R-
1150, 2-BTP, EXXFIRE[supreg], and Powdered Aerosol H in the end-uses
addressed in this action would provide additional lower-GWP and ODP or
comparable alternatives in their respective end-uses. By providing
lower-GWP and ODP or comparable alternatives for these end-uses, this
proposed rule is also anticipated to reduce the use and eventual
emissions of potent GHGs in this end-use, which could help to reduce
the effects of climate change, including the public health and welfare
effects on people of color, communities of low-income and/or indigenous
peoples. This action's health and environmental risk assessments are
contained in the comparison of health and environmental risks for HFC-
32, HFO-1234yf, R-452B, R-454A, R-454B, R-454C, R-1150, 2-BTP,
EXXFIRE[supreg], and Powdered Aerosol H, as well as in the risk screens
that are available in the docket for this rulemaking. EPA's analysis
indicates that other environmental impacts and human health impacts of
HFC-32, HFO-1234yf, R-452B, R-454A, R-454B, R-454C, R-1150, 2-BTP,
EXXFIRE[supreg], and Powdered Aerosol H are comparable to or less than
those of other substitutes that are listed as acceptable for the same
end-use. Based on these considerations, EPA expects that the effects on
people of color, communities of low-income and/or indigenous peoples
would not be disproportionately high and adverse.

V. References

    Unless specified otherwise, all documents are available
electronically through the Federal Docket Management System at
regulations.gov, Docket number EPA-HQ-OAR-2021-0836.

ASHRAE, 2019a. ANSI/ASHRAE Standard 34-2019: Designation and Safety
Classification of Refrigerants.
ASHRAE, 2019b. ANSI/ASHRAE Standard 15-2019: Safety Standard for
Refrigeration Systems. 2019.
Brioude et al., 2010. Brioude, J., R.W. Portmann, J.S. Daniel, O.R.
Cooper, G.J. Frost, K.H. Rosenlof, C. Granier, A.R. Ravishankara,
S.A. Montzka, and A. Stohl, Variations in ozone depletion potentials
of very short-lived substances with season and emission region,
Geophys. Res. Lett., 37, L19804, doi:10.1029/2010GL044856, 2010.
Hodnebrog, et al., 2013. Hodnebrog, [Oslash]., Etminan, M.,
Fuglestvedt, J.S., Marston, G., Myhre, G., Nielsen, C.J., Shine,
K.P., and Wallington, T.J. (2013). Global Warming Potentials and
Radiative Efficiencies of Halocarbons and Related Compounds: A
Comprehensive Review, Reviews of Geophysics, 51, 300-378. Available
online at doi.org/10.1002/rog.20013.
EPA, 2004. A Guide to Completing a Risk Screen: Collection and Use
of Risk Screen Data. Fire Suppression Sector. April, 2004.
ICF, 2014. Assessment of the Potential Impact of Hydrocarbon
Refrigerants on Ground Level Ozone Concentrations. February, 2014.
ICF, 2022a. Risk Screen on Substitutes in Chillers and Industrial
Process Air Conditioning (New Equipment); Substitute: R-32.
ICF, 2022b. Risk Screen on Substitutes in Chillers and Industrial
Process Air Conditioning (New Equipment); Substitute: HFO-123yf.
ICF, 2022c. Risk Screen on Substitutes in Chillers and Industrial
Process Air Conditioning (New Equipment); Substitute: R-452B.
ICF, 2022d. Risk Screen on Substitutes in Chillers and Industrial
Process Air Conditioning (New Equipment); Substitute: R-454A.
ICF, 2022e. Risk Screen on Substitutes in Chillers and Industrial
Process Air Conditioning (New Equipment); Substitute: R-454B.
ICF, 2022f. Risk Screen on Substitutes in Chillers and Industrial
Process Air Conditioning (New Equipment); Substitute: R-454C.
ICF, 2022g. Risk Screen on Substitutes in Residential Dehumidifiers
(New Equipment); Substitute: HFC-32.
ICF, 2022h. Risk Screen on Substitutes in Residential Dehumidifiers
(New Equipment); Substitute: R-452B.
ICF, 2022i. Risk Screen on Substitutes in Residential Dehumidifiers
(New Equipment); Substitute: R-454A.
ICF, 2022j. Risk Screen on Substitutes in Residential Dehumidifiers
(New Equipment); Substitute: R-454B.

ICF, 2022k. Risk Screen on Substitutes in Residential Dehumidifiers
(New Equipment); Substitute: R-454C.
ICF, 2022l. Risk Screen on Substitutes in Residential Dehumidifiers
(New Equipment); Substitute: HFO-1234yf
ICF, 2022m. Risk Screen on Substitutes in Non-residential
Dehumidifiers (New Equipment); Substitute: HFC-32.
ICF, 2022n. Risk Screen on Substitutes in Residential and Light
Commercial Air Conditioning and Heat Pumps (New Equipment);
Substitute: HFC-32 (Difluoromethane).
ICF, 2022o. Risk Screen on Substitutes in Very Low Temperature
Refrigeration (New Equipment); Substitute: R-1150.
ICF, 2022p. Additional Assessment of the Potential Impact of
Hydrocarbon Refrigerants on Ground Level Ozone Concentrations. May,
2020.
ICF, 2022q. Risk Screen on Substitutes in Total Flooding Systems in
Normally Unoccupied Spaces. Substitute: 2-bromo-3,3,3-
trifluoropropene (2-BTP).
ICF, 2022r. Risk Screen on Substitutes as Streaming Agents in Non-
Residential Applications. Substitute: 2-bromo-3,3,3-trifluoropropene
(2-BTP).
ICF, 2022s. Risk Screen on Substitutes in Total Flooding Systems in
Normally Unoccupied Spaces; Substitute: EXXFIRE[supreg].
ICF, 2022t. Risk Screen on Substitutes in Total Flooding Systems in
Normally Unoccupied Spaces; Substitute: Pyroquench-
[alpha]TM.
IPCC, 2007. Climate Change 2007: The Physical Science Basis.
Contribution of Working Group I to the Fourth Assessment Report of
the Intergovernmental Panel on Climate Change. Solomon, S., Qin, D.,
Manning, M., Chen, Z., Marquis, M., Averyt, K.B., Tignor, M., and
Miller, H.L. (eds.). Cambridge University Press. Cambridge, United
Kingdom and New York, NY, USA. Available online at: www.ipcc.ch/
publications_and_data/ar4/wg1/en/contents.html.
National Fire Protection Agency (NFPA). 2018. NFPA 10: Standard for
Portable Fire Extinguishers.
National Fire Protection Agency (NFPA). 2018. NFPA 2001: Standard on
Clean Agent Fire Extinguishing Systems.
National Fire Protection Agency (NFPA). 2018. NFPA 2010. Standard
for Fixed Aerosol Fire Extinguishing Systems.
Nielsen et al., 2007. Nielsen, O.J., Javadi, M.S., Sulbaek Andersen,
M.P., Hurley, M.D., Wallington, T.J., Singh, R. (2007). Atmospheric
chemistry of CF3CF=CH2: Kinetics and mechanisms of gas-phase
reactions with Cl atoms, OH radicals, and O3. Chemical Physics
Letters 439, 18-22. Available online at http://www.lexissecuritiesmosaic.com/gateway/FedReg/network_OJN_174_CF3CF=CH2.pdf.
UL 2129, 2017. UL Standard 2129--Halocarbon Clean Agent Fire
Extinguishers. Edition 3.
UL 60335-2-40, 2019. Household And Similar Electrical Appliances--
Safety--Part 2-40: Particular Requirements for Electrical Heat
Pumps, Air-Conditioners and Dehumidifiers. Third Edition. November
1, 2019.
UL Standard 61010-2-011, 2021. Safety Requirements for Electrical
Equipment for Measurement, Control, and Laboratory Use--Part 011:
Particular Requirements for Refrigerating Equipment. Second edition.
May 13, 2021.
Wickham, 2002. Status of Industry Efforts to Replace Halon Fire
Extinguishing Agents. March 2002. Available online at: https://www.epa.gov/snap/status-industry-efforts-replace-halon-fire-extinguishing-agents.
World Meteorological Organization (WMO), 2018. Burkholder et al.
Appendix A, Table A-1 in Scientific Assessment of Ozone Depletion:
2018, Global Ozone Research and Monitoring Project, Report No. 58,
World Meteorological Organization, Geneva, Switzerland, http://ozone.unep.org/science/assessment/sap.
Youn et al. (2010). Youn, D., K.O. Patten, D.J. Wuebbles, H. Lee,
and C.-W. So, Potential impact of iodinated replacement compounds
CF3I and CH3I on atmospheric ozone: A three-
dimensional modeling study, Atmos. Chem. Phys., 10, 10,129-10,144,
doi:10.5194/acp-10-10129-2010, 2010.

List of Subjects in 40 CFR Part 82

    Environmental protection, Administrative practice and procedure,
Air pollution control, Incorporation by reference, Stratospheric ozone
layer.

Michael S. Regan,
Administrator.

    For the reasons set forth in the preamble, EPA proposes to amend 40
CFR part 82 as follows:

PART 82--PROTECTION OF STRATOSPHERIC OZONE

0
1. The authority citation for part 82 continues to read as follows:

    Authority:  42 U.S.C. 7414, 7601, 7671-7671q.

Subpart G-Significant New Alternatives Policy Program

0
2. Amend appendix R to subpart G of part 82 by:
0
a. Revising the heading for appendix R to subpart G of part 82;
0
b. Revising the table titled ``Substitutes That Are Acceptable Subject
to Use Conditions''; and
0
c. Removing the two undesignated paragraphs immediately preceding table
A.
    The revisions read as follows:

Appendix R to Subpart G of Part 82--Substitutes Subject to Use
Restrictions Listed in the December 20, 2011, Final Rule, Effective
February 21, 2012, and in the April 10, 2015 Final Rule, Effective May
11, 2015, and in the [Date of Publication of the Final Rule in the
Federal Register] Final Rule, Effective [Date 30 Days After Date of
Publication of the Final Rule in the Federal Register]

                                                Substitutes That Are Acceptable Subject to Use Conditions
--------------------------------------------------------------------------------------------------------------------------------------------------------
            End-use                Substitute         Decision                         Use conditions                          Further information
--------------------------------------------------------------------------------------------------------------------------------------------------------
1. Household refrigerators,     Isobutane (R-     Acceptable        As of September 7, 2018: These refrigerants may be   Applicable OSHA requirements at
 freezers, and combination       600a) Propane     subject to use    used only in new equipment designed specifically     29 CFR part 1910 must be
 refrigerators and freezers      (R-290) R-441A.   conditions.       and clearly identified for the refrigerant (i.e.,    followed, including those at
 (New equipment only).                                               none of these substitutes may be used as a           29 CFR 1910.106 (flammable and
                                                                     conversion or ``retrofit'' refrigerant for           combustible liquids), 1910.110
                                                                     existing equipment designed for a different          (storage and handling of
                                                                     refrigerant)                                         liquefied petroleum gases),
                                                                    These refrigerants may be used only in a              1910.157 (portable fire
                                                                     refrigerator or freezer, or combination              extinguishers), and 1910.1000
                                                                     refrigerator and freezer, that meets all             (toxic and hazardous
                                                                     requirements listed in UL 60335-2-24 1 2 6           substances).
                                                                                Proper ventilation should be
                                                                                maintained at all times during
                                                                                the manufacture and storage of
                                                                                equipment containing
                                                                                hydrocarbon refrigerants
                                                                                through adherence to good
                                                                                manufacturing practices as per
                                                                                29 CFR 1910.106. If
                                                                                refrigerant levels in the air
                                                                                surrounding the equipment rise
                                                                                above one-fourth of the lower
                                                                                flammability limit, the space
                                                                                should be evacuated and re-
                                                                                entry should occur only after
                                                                                the space has been properly
                                                                                ventilated.
                                                                                Technicians and equipment
                                                                                manufacturers should wear
                                                                                appropriate personal
                                                                                protective equipment,
                                                                                including chemical goggles and
                                                                                protective gloves, when
                                                                                handling these refrigerants.
                                                                                Special care should be taken
                                                                                to avoid contact with the skin
                                                                                since these refrigerants, like
                                                                                many refrigerants, can cause
                                                                                freeze burns on the skin.
                                                                                A Class B dry powder type fire
                                                                                extinguisher should be kept
                                                                                nearby.
                                                                                Technicians should only use
                                                                                spark-proof tools when working
                                                                                on refrigerators and freezers
                                                                                with these refrigerants.
                                                                                Any recovery equipment used
                                                                                should be designed for
                                                                                flammable refrigerants. Any
                                                                                refrigerant releases should be
                                                                                in a well-ventilated area,
                                                                                such as outside of a building.
                                                                                Only technicians specifically
                                                                                trained in handling flammable
                                                                                refrigerants should service
                                                                                refrigerators and freezers
                                                                                containing these refrigerants.
                                                                                Technicians should gain an
                                                                                understanding of minimizing
                                                                                the risk of fire and the steps
                                                                                to use flammable refrigerants
                                                                                safely.

2. Retail food refrigerators    Isobutane (R-     Acceptable        As provided in clauses SB6.1.2 to SB6.1.5 of UL      Room occupants should evacuate
 and freezers (stand-alone       600a) Propane     subject to use    471,1 2 3 the following markings must be attached    the space immediately
 units only) (New equipment      (R-290) R-441A.   conditions.       at the locations provided and must be permanent:     following the accidental
 only).                                                             (a) On or near any evaporators that can be            release of this refrigerant.
                                                                     contacted by the consumer: ``DANGER--Risk of Fire   If a service port is added then
                                                                     or Explosion. Flammable Refrigerant Used. Do Not     retail food refrigerators and
                                                                     Use Mechanical Devices To Defrost Refrigerator. Do   freezers using these
                                                                     Not Puncture Refrigerant Tubing.''                   refrigerants should have
                                                                    (b) Near the machine compartment: ``DANGER--Risk of   service aperture fittings that
                                                                     Fire or Explosion. Flammable Refrigerant Used. To    differ from fittings used in
                                                                     Be Repaired Only By Trained Service Personnel. Do    equipment or containers using
                                                                     Not Puncture Refrigerant Tubing.''                   non-flammable refrigerant.
                                                                    (c) Near the machine compartment: ``CAUTION--Risk     ``Differ'' means that either
                                                                     of Fire or Explosion. Flammable Refrigerant Used.    the diameter differs by at
                                                                     Consult Repair Manual/Owner's Guide Before           least 1/16 inch or the thread
                                                                     Attempting To Service This Product. All Safety       direction is reversed (i.e.,
                                                                     Precautions Must be Followed.''                      right-handed vs. left-handed).
                                                                    (d) On the exterior of the refrigerator: ``CAUTION--  These different fittings
                                                                     Risk of Fire or Explosion. Dispose of Properly In    should be permanently affixed
                                                                     Accordance With Federal Or Local Regulations.        to the unit at the point of
                                                                     Flammable Refrigerant Used.''                        service and maintained until
                                                                    (e) Near any and all exposed refrigerant tubing:      the end-of-life of the unit,
                                                                     ``CAUTION--Risk of Fire or Explosion Due To          and should not be accessed
                                                                     Puncture Of Refrigerant Tubing; Follow Handling      with an adaptor.
                                                                     Instructions Carefully. Flammable Refrigerant
                                                                     Used.''
                                                                    All of these markings must be in letters no less
                                                                     than 6.4 mm (\1/4\ inch) high.
                                                                    The refrigerator or freezer must have red,
                                                                     Pantone[supreg] Matching System (PMS) #185 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.

3. Very low temperature         Ethane (R-170)..  Acceptable        This refrigerant may be used only in new equipment   Applicable OSHA requirements at
 refrigeration Non-mechanical                      subject to use    specifically designed and clearly identified for     29 CFR part 1910 must be
 heat transfer (New equipment                      conditions.       the refrigerant (i.e., the substitute may not be     followed, including those at
 only).                                                              used as a conversion or ``retrofit'' refrigerant     29 CFR 1910.94 (ventilation)
                                                                     for existing equipment designed for other            and 1910.106 (flammable and
                                                                     refrigerants).                                       combustible liquids), 1910.110
                                                                    This refrigerant may only be used in equipment that   (storage and handling of
                                                                     meets all requirements in Supplement SB to, UL       liquefied petroleum gases),
                                                                     471.1 32 3 In cases where listing 3 or 4 of this     1910.157 (portable fire
                                                                     table includes requirements more stringent than      extinguishers), and 1910.1000
                                                                     those of UL 471, the appliance must meet the         (toxic and hazardous
                                                                     requirements of listing 3 or 4 of this table in      substances).
                                                                     place of the requirements in UL 471.                Proper ventilation should be
                                                                    The charge size for the equipment must not exceed     maintained at all times during
                                                                     150 g (5.29 oz) in each circuit.                     the manufacture and storage of
                                                                                equipment containing
                                                                                hydrocarbon refrigerants
                                                                                through adherence to good
                                                                                manufacturing practices as per
                                                                                29 CFR 1910.106. If
                                                                                refrigerant levels in the air
                                                                                surrounding the equipment rise
                                                                                above one-fourth of the lower
                                                                                flammability limit, the space
                                                                                should be evacuated and re-
                                                                                entry should occur only after
                                                                                the space has been properly
                                                                                ventilated.
                                                                                Technicians and equipment
                                                                                manufacturers should wear
                                                                                appropriate personal
                                                                                protective equipment,
                                                                                including chemical goggles and
                                                                                protective gloves, when
                                                                                handling ethane. Special care
                                                                                should be taken to avoid
                                                                                contact with the skin since
                                                                                ethane, like many
                                                                                refrigerants, can cause freeze
                                                                                burns on the skin.
                                                                                A Class B dry powder type fire
                                                                                extinguisher should be kept
                                                                                nearby.
                                                                                Technicians should only use
                                                                                spark-proof tools when working
                                                                                on equipment with flammable
                                                                                refrigerants.
                                                                                Any recovery equipment used
                                                                                should be designed for
                                                                                flammable refrigerants.
                                                                                Any refrigerant releases should
                                                                                be in a well-ventilated area,
                                                                                such as outside of a building.
                                                                                Only technicians specifically
                                                                                trained in handling flammable
                                                                                refrigerants should service
                                                                                equipment containing ethane.
                                                                                Technicians should gain an
                                                                                understanding of minimizing
                                                                                the risk of fire and the steps
                                                                                to use flammable refrigerants
                                                                                safely.

4. Very low temperature         Ethane (R-170)..  Ethane (R-170)..  As provided in clauses SB6.1.2 to SB6.1.5 of UL      Room occupants should evacuate
 refrigeration. Non-mechanical                                       471,1 2 3 the following markings must be attached    the space immediately
 heat transfer (New equipment                                        at the locations provided and must be permanent:     following the accidental
 only).                                                             (a) On or near any evaporators that can be            release of this refrigerant.
                                                                     contacted by the consumer: ``DANGER--Risk of Fire   If a service port is added then
                                                                     or Explosion. Flammable Refrigerant Used. Do Not     refrigeration equipment using
                                                                     Use Mechanical Devices To Defrost Refrigerator. Do   this refrigerant should have
                                                                     Not Puncture Refrigerant Tubing.''                   service aperture fittings that
                                                                    (b) Near the machine compartment: ``DANGER--Risk of   differ from fittings used in
                                                                     Fire or Explosion. Flammable Refrigerant Used. To    equipment or containers using
                                                                     Be Repaired Only By Trained Service Personnel. Do    non-flammable refrigerant.
                                                                     Not Puncture Refrigerant Tubing.''                   ``Differ'' means that either
                                                                    (c) Near the machine compartment: ``CAUTION--Risk     the diameter differs by at
                                                                     of Fire or Explosion. Flammable Refrigerant Used.    least \1/16\ inch or the
                                                                     Consult Repair Manual/Owner's Guide Before           thread direction is reversed
                                                                     Attempting To Service This Product. All Safety       (i.e., right-handed vs. left-
                                                                     Precautions Must be Followed.''                      handed). These different
                                                                    (d) On the exterior of the refrigerator: ``CAUTION--  fittings should be permanently
                                                                     Risk of Fire or Explosion. Dispose of Properly In    affixed to the unit at the
                                                                     Accordance With Federal Or Local Regulations.        point of service and
                                                                     Flammable Refrigerant Used.''                        maintained until the end-of-
                                                                    (e) Near any and all exposed refrigerant tubing:      life of the unit, and should
                                                                     ``CAUTION--Risk of Fire or Explosion Due To          not be accessed with an
                                                                     Puncture Of Refrigerant Tubing; Follow Handling      adaptor.
                                                                     Instructions Carefully. Flammable Refrigerant       Example of non-mechanical heat
                                                                     Used.''                                              transfer using this
                                                                    All of these markings must be in letters no less      refrigerant would be use in a
                                                                     than 6.4 mm (\1/4\ inch) high.                       secondary loop of a
                                                                    The refrigeration equipment must have red,            thermosiphon.
                                                                     Pantone[supreg] Matching System (PMS) #185 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.

5. Vending Machines (New        Isobutane (R-     Acceptable        These refrigerants may be used only in new           Applicable OSHA requirements at
 equipment only).                600a) Propane     subject to use    equipment specifically designed and clearly          29 CFR part 1910 must be
                                 (R-290) R-441A.   conditions.       identified for the refrigerants (i.e., none of       followed, including those at
                                                                     these substitutes may be used as a conversion or     29 CFR 1910.94 (ventilation)
                                                                     ``retrofit'' refrigerant for existing equipment      and 1910.106 (flammable and
                                                                     designed for other refrigerants). Detaching and      combustible liquids), 1910.110
                                                                     replacing the old refrigeration circuit from the     (storage and handling of
                                                                     outer casing of the equipment with a new one         liquefied petroleum gases),
                                                                     containing a new evaporator, condenser, and          1910.157 (portable fire
                                                                     refrigerant tubing within the old casing is          extinguishers), and 1910.1000
                                                                     considered ``new'' equipment and not a retrofit of   (toxic and hazardous
                                                                     the old, existing equipment.                         substances).
                                                                    These substitutes may only be used in equipment      Proper ventilation should be
                                                                     that meets all requirements in Supplement SA to UL   maintained at all times during
                                                                     541.1 2 5 In cases where listing 5 or 6 of this      the manufacture and storage of
                                                                     table includes requirements more stringent than      equipment containing
                                                                     those of UL 541, the appliance must meet the         hydrocarbon refrigerants
                                                                     requirements of listing 5 or 6 of this table in      through adherence to good
                                                                     place of the requirements in UL 541. The charge      manufacturing practices as per
                                                                     size for vending machines must not exceed 150 g      29 CFR 1910.106. If
                                                                     (5.29 oz) in each circuit.                           refrigerant levels in the air
                                                                                surrounding the equipment rise
                                                                                above one-fourth of the lower
                                                                                flammability limit, the space
                                                                                should be evacuated and re-
                                                                                entry should occur only after
                                                                                the space has been properly
                                                                                ventilated.
                                                                                Technicians and equipment
                                                                                manufacturers should wear
                                                                                appropriate personal
                                                                                protective equipment,
                                                                                including chemical goggles and
                                                                                protective gloves, when
                                                                                handling these refrigerants.
                                                                                Special care should be taken
                                                                                to avoid contact with the skin
                                                                                since these refrigerants, like
                                                                                many refrigerants, can cause
                                                                                freeze burns on the skin.
                                                                                A Class B dry powder type fire
                                                                                extinguisher should be kept
                                                                                nearby.
                                                                                Technicians should only use
                                                                                spark-proof tools when working
                                                                                on refrigeration equipment
                                                                                with flammable refrigerants.
                                                                                Any recovery equipment used
                                                                                should be designed for
                                                                                flammable refrigerants.
                                                                                Any refrigerant releases should
                                                                                be in a well-ventilated area,
                                                                                such as outside of a building.
                                                                                Only technicians specifically
                                                                                trained in handling flammable
                                                                                refrigerants should service
                                                                                refrigeration equipment
                                                                                containing these refrigerants.
                                                                                Technicians should gain an
                                                                                understanding of minimizing
                                                                                the risk of fire and the steps
                                                                                to use flammable refrigerants
                                                                                safely.

6. Vending Machines (New        Isobutane (R-     Acceptable        As provided in clauses SA6.1.2 to SA6.1.5 of UL      Room occupants should evacuate
 equipment only).                600a) Propane     subject to use    541,1 2 5 the following markings must be attached    the space immediately
                                 (R-290) R-441A.   conditions.       at the locations provided and must be permanent:     following the accidental
                                                                    (a) On or near any evaporators that can be            release of this refrigerant.
                                                                     contacted by the consumer: ``DANGER--Risk of Fire   If a service port is added then
                                                                     or Explosion. Flammable Refrigerant Used. Do Not     refrigeration equipment using
                                                                     Use Mechanical Devices To Defrost Refrigerator. Do   this refrigerant should have
                                                                     Not Puncture Refrigerant Tubing.''                   service aperture fittings that