the atmosphere. In that extreme scenario, the model predicted that the
maximum increase in any single 8-hour average ground-level ozone
concentration would be 0.72 ppb in Los Angeles, which is the area with
the highest level of ozone pollution in the United States. Given the
potential sources of uncertainty in the modeling, the conservativeness
of the assumptions, and the finding that the incremental VOC emissions
from refrigerant emissions would not cause any area that otherwise
would meet the 2008 ozone NAAQS to exceed it,\44\ we believe that the
use of isobutane consistent with the use conditions required in EPA's
regulations will not result in significantly greater risk to the
environment than other alternatives. Further, propane is less reactive
than isobutane and thus we reach a similar conclusion for propane.
---------------------------------------------------------------------------

    \43\ Ibid.
    \44\ The analysis described here was conducted prior to
finalization of the 2015 ozone NAAQS. EPA has not yet made ozone
attainment area designations for the 2015 ozone NAAQS.
---------------------------------------------------------------------------

    In a less conservative analysis potential impacts on ambient ozone
levels, EPA looked at a set of end-uses that would be more likely to
use HC refrigerants between now and 2030, including end-uses where they
previously have been listed as acceptable and where they are proposed
to be acceptable under this rule. For example, we assumed use of
propane in water coolers and commercial ice machines and in end-uses
where it is listed as acceptable, including room air conditioners and
household and retail food refrigeration equipment and we assumed the
use of other HCs such as isobutane in household and retail food
refrigeration equipment and R-441A in room air conditioners and
household and retail food refrigeration equipment. For further
information on the specific assumptions, see the docket for this
rulemaking \45\ Based on this still conservative but more probable
assessment of refrigerant use, we found that even if all the
refrigerant in appliances in end-uses addressed in this proposed rule
and in appliances in end-uses for which HCs are listed as acceptable
were to be emitted, there would be a worst-case impact of a 0.15 ppb
increase in ozone for a single 8-hour average concentration in the Los
Angeles area, which is the area with the highest level of ozone
pollution in the United States.\46\ In the other cities examined in the
analysis, Houston and Atlanta, impacts were smaller (no more than 0.03
and 0.01 ppb for a single 8-hour average concentration,
respectively).\47\ For areas in the analysis that were not violating
the 2008 ozone NAAQS, the impacts did not cause an exceedance of the
2008 ozone NAAQS.
---------------------------------------------------------------------------

    \45\ ICF, 2014a. Assessment of the Potential Impact of
Hydrocarbon Refrigerants on Ground Level Ozone Concentrations.
February, 2014.
    \46\ This less conservative analysis included some use of R-443A
in room AC units because that substitute was under evaluation for
that end-use. Elsewhere in this proposal, we propose to find R-443A
and propylene unacceptable in residential and light-commercial AC
and heat pumps, including room AC units. The propylene in R-443A,
representing 12 percent of refrigerant emitted, was responsible for
about 75 percent of the 0.15 ppb increase in ozone in this scenario,
while all uses of propane, representing 83 percent of refrigerant
emitted, was responsible for about 21 percent of the increase of
ozone in this scenario. Thus, only 0.03 ppb of the o.15 ppb observed
in Los Angeles would be due to propane and other acceptable HCs.
    \47\ ICF, 2014a. Assessment of the Potential Impact of
Hydrocarbon Refrigerants on Ground Level Ozone Concentrations.
February, 2014.
---------------------------------------------------------------------------

    Because of the relatively low air quality impacts of propane if it
is

released to the atmosphere from the proposed end-uses even in a worst-
case scenario, we propose that propane does not have a significantly
greater overall impact on human health and the environment based on its
effects on local air quality than other refrigerants listed as
acceptable in commercial ice machines, water coolers, and very low
temperature refrigeration equipment.
    Propane is highly volatile and typically evaporates or partitions
to air, rather than contaminating surface waters. Propane's effects on
aquatic life are expected to be small and pose no greater risk of
aquatic or ecosystem effects than those of other alternatives for these
uses.
ii. Flammability
    Propane's flammability risks are of potential concern because
commercial ice machines, water coolers, and very low temperature
refrigeration equipment have traditionally used refrigerants that are
not flammable. Without appropriate use conditions, the flammability
risk posed by propane would be higher than non-flammable refrigerants
because individuals may not be aware that their actions could
potentially cause a fire. In this section, we discuss the flammability
risks posed by propane and identify proposed use conditions that would
mitigate those risks such that propane would not pose significantly
greater risk due to flammability than other substitutes in these end-
uses.
    Because of its flammability, propane could pose a significant
safety concern for workers and consumers in the end-uses addressed in
this proposal if it is not handled correctly. In the presence of an
ignition source (e.g., static electricity spark resulting from closing
a door, use of a torch during service, or a short circuit in wiring
that controls the motor of a compressor), an explosion or a fire could
occur when the concentration of refrigerant exceeds its lower
flammability limit (LFL). Propane's LFL is 21,000 ppm (2.1%).
Therefore, to use propane safely, it is important to minimize the
presence of potential ignition sources and to reduce the likelihood
that the concentration of propane will exceed the LFL. Under the
proposed listing decision, propane would be acceptable for use only in
new equipment (self-contained commercial ice machines, water coolers,
and very low temperature refrigeration equipment) specifically designed
for this refrigerant. OSHA and building code requirements generally
address flammability risks in the workplace and we presume that the
original equipment manufacturers (OEMs), who would be storing large
quantities of the refrigerant, are familiar with and use proper safety
precautions to minimize the risk of explosion, consistent with those
requirements. Therefore, we are not proposing use conditions to address
workplace risk, which would be redundant of already existing
requirements. We are proposing, however, to include recommendations in
the ``Further Information'' section of the SNAP listings that these
facilities be equipped with proper ventilation systems and be properly
designed to reduce possible ignition sources.
    To determine whether flammability would be a concern for service
personnel or for consumers, EPA analyzed a plausible worst-case
scenario to model a catastrophic release of propane. The worst-case
scenario analysis for water coolers and for very low temperature
refrigeration equipment revealed that even if the unit's full charge is
emitted within one minute, the leaked refrigerant concentration did not
reach propane's LFL of 2.1%, provided that the charge sizes were no
greater than those specified in the relevant standard from
UL.48 49 We are proposing the maximum charge size specified
in the standard as a use condition; thus, there would not be an
unacceptable risk of fire or explosion, even under those worst-case
assumptions, so long as the charge does not exceed the use conditions
in this proposed rule. In the case of commercial ice machines, the
worst-case scenario with use of a charge size of 150 g and assuming
stratification of refrigerant into the bottom 0.4 m of the room
resulted in attaining 102 percent of the LFL; less conservative, but
reasonable, assumptions (e.g., larger room size, greater mixing of the
refrigerant in the entire room, same charge size of 150 g) resulted in
concentrations at 18 percent or less of the LFL.\50\ Thus, we expect
there would not be an unacceptable risk of fire or explosion provided
that the charge size is limited to 150 g. EPA also reviewed the
submitters' detailed assessments of the probability of events that
might create a fire and approaches to avoid sparking from the
refrigeration equipment. Further information on these analyses and
EPA's risk assessments are available in the docket for this rulemaking
(EPA-HQ-OAR-2015-0663). Further, service personnel or consumers may not
be familiar with refrigeration or AC equipment containing a flammable
refrigerant. Therefore, use conditions are necessary to ensure people
handling such equipment are aware that equipment contains a flammable
refrigerant and to ensure safe handling.
---------------------------------------------------------------------------

    \48\ ICF, 2016c. Significant New Alternatives Policy Program:
Refrigeration and Air Conditioning Sector Risk Screen on Substitutes
in Water Coolers Substitute: Propane (R-290).
    \49\ ICF, 2016d. Significant New Alternatives Policy Program:
Refrigeration and Air Conditioning Sector Risk Screen on Substitutes
in Very Low Temperature Refrigeration Substitute: Propane (R-290)
and Ethane (R-170).
    \50\ ICF, 2016e. Significant New Alternatives Policy Program:
Refrigeration and Air Conditioning Sector Risk Screen on Substitutes
in Commercial Ice Machines Substitute: Propane (R-290).
---------------------------------------------------------------------------

iii. Toxicity
    In evaluating potential toxicity impacts of propane on human health
in these end-uses, EPA considered both occupational and consumer risks.
In general when evaluating non-cancer toxicity risks of a substitute,
we use measured exposure concentrations if available, or modeled
exposure concentrations using conservative assumptions appropriate to
an end-use, and compare these exposure levels to recommended or
required exposure limits for a compound that are intended to protect
against adverse health effects. Where measured or modeled exposure
levels are below relevant exposure limits for a chemical, we consider
toxicity risks to be acceptable. Other acceptable substitutes listed
for these end-uses have been evaluated for toxicity in this manner,
including ethane for very low temperature refrigeration, ammonia for
commercial ice machines, and a number of HFC blends for all three end-
uses.
    EPA investigated the risk of asphyxiation and of exposure to toxic
levels of refrigerant for a worst-case scenario and a typical use. In
the worst-case scenario of a catastrophic leak, we modeled release of
the unit's full charge within one minute into a confined space to
estimate concentrations that might result. We considered a
conservatively small space appropriate to each end-use, such as a small
galley kitchen of 18 m\3\ for a water cooler, a kitchen of a fast food
restaurant of 22 m\3\ for a commercial ice machine or in a laboratory
module of 28 m\3\ for very low temperature refrigeration equipment.
    To evaluate the toxicity of propane, EPA estimated the maximum time
weighted average (TWA) exposure both for a short-term exposure
scenario, with a 30-minute TWA exposure, and for an 8-hour TWA that
would be more typical of occupational exposure for a technician
servicing the equipment or a worker disposing of appliances. We
compared these short-term and long-term exposure values to relevant
industry and government workplace exposure limits for propane. The
modeling results indicate that both the

short-term (30-minute) and long-term (8-hour) worker exposure
concentrations would be below the relevant workplace exposure limits,
such as the OSHA PEL of 1000 ppm (8-hr TWA), and the National Research
Council's Acute Emergency Guideline Limit Level 1 (AEGL-1) \51\ of
6,900 ppm over 30 minutes.
---------------------------------------------------------------------------

    \51\ The AEGL limit is an emergency guideline for exposures to
the general population (including susceptible populations) and is
not time-weighted. It also considers the chemical's flammability in
addition to its toxicity. EPA develops a set of AEGL values for a
substance for five exposure periods (10 and 30 minutes, 1 hour, 4
hours and 8 hours). For each exposure period, three different AEGL
values are developed to address different levels of toxicological
impacts. Of relevance for the modeled scenario is the AEGL-1, which
is defined as: ``the airborne concentration, expressed as parts per
million or milligrams per cubic meter (ppm or mg/m\3\) of a
substance above which it is predicted that the general population,
including susceptible individuals, could experience notable
discomfort, irritation, or certain asymptomatic nonsensory effects.
However, the effects are not disabling and are transient and
reversible upon cessation of exposure.'' While permanent
toxicological effects are not expected up to the AEGL-2 value, this
limit is not relevant for this analysis because at that level,
flammability would be a greater concern.
---------------------------------------------------------------------------

    A similar analysis of asphyxiation risks considered whether a
worst-case release of refrigerant in the same room sizes would result
in oxygen concentrations of 12 percent or less. This analysis found
that impacts on oxygen concentrations were minimal, with oxygen
concentrations remaining at approximately 21 percent.
    For equipment with which consumers might come into contact, such as
water coolers and commercial ice machines, EPA performed a consumer
exposure analysis. In this analysis, we examined potential catastrophic
release of the entire charge of the substitute in one minute under a
worst-case scenario. We did not examine exposure to consumers in very
low temperature refrigeration, as equipment for this end-use would
typically be used in the workplace, such as in laboratories, and not in
a home or public space. The analysis was undertaken to determine the
30-minute TWA exposure levels for the substitute, which were then
compared to the toxicity limit to assess the risk to consumers.
    EPA considered toxicity limits for consumer exposure that reflect a
short-term exposure such as might occur at home or in a store or other
public setting where a member of the general public could be exposed
and could then escape. The toxicity limit that we used in our analysis
of consumer exposure was an AEGL-1 of 6,900 ppm over 30 minutes. The
analysis of consumer exposure assumed that 100 percent of the unit's
charge would be released over one minute, at which time the
concentration of refrigerant would peak in an enclosed space, and then
steadily decline. Refrigerant concentrations were modeled under two air
change scenarios, believed to represent the baseline of potential flow
rates for a home or public space, assuming flow rates of 2.3 air
changes per hour (ACH) in a household kitchen and 20 ACH in a
restaurant kitchen.52 53 The highest concentrations of the
refrigerant occur in the lower stratum of the room when assuming the
lower ventilation level of 2.3 ACH. Calculating the TWA exposure using
2.3 ACH results in a higher concentration than calculating the TWA
exposure using 20 ACH. Even under the very conservative assumptions
used in the consumer exposure modeling, the estimated 30-minute
consumer exposures to propane are lower than the relevant toxicity
limits.
---------------------------------------------------------------------------

    \52\ ICF, 2016c. Significant New Alternatives Policy Program:
Refrigeration and Air Conditioning Sector Risk Screen on Substitutes
in Water Coolers Substitute: Propane (R-290).
    \53\ ICF, 2016e. Significant New Alternatives Policy Program:
Refrigeration and Air Conditioning Sector Risk Screen on Substitutes
in Commercial Ice Machines Substitute: Propane (R-290).
---------------------------------------------------------------------------

    Based upon our analysis, workplace and consumer exposure to propane
when used in these end-uses according to the proposed use conditions is
not expected to exceed relevant exposure limits. Thus, propane does not
pose significantly greater toxicity risks to other acceptable
refrigerants in these end-uses. For further information, including
EPA's risk screens and risk assessments as well as information from the
submitters of propane as a substitute refrigerant, see docket EPA-HQ-
OAR-2015-0663.
c. What are the proposed use conditions?
    In order to ensure that use of propane in these three end-uses
would not cause greater risk to human health or the environment than
use of other alternatives, we have identified and are proposing use
conditions to address flammability and toxicity concerns. The proposed
use conditions include conditions consistent with industry standards,
limits on charge size, and requirements for warnings and markings on
equipment.
i. New Equipment Only; Not Intended for Use as a Retrofit Alternative
    EPA is proposing that, in the specified end-uses, propane be
limited to use only in new equipment \54\ that has been designed and
manufactured specifically for use with propane. Propane was not
submitted under the SNAP program to be used in retrofitted equipment,
and no information was provided on how to mitigate hazards of flammable
refrigerants when used in equipment that was not designed for flammable
refrigerants. If this use condition is finalized as proposed, use of
propane in equipment not designed for its use, including existing
equipment designed for another refrigerant, would be in violation of
CAA section 612(c) and the corresponding SNAP regulations at 40 CFR
part 82, subpart G.
---------------------------------------------------------------------------

    \54\ This is intended to mean a completely new refrigeration
circuit containing a new evaporator, condenser and refrigerant
tubing.
---------------------------------------------------------------------------

ii. Standards
    EPA is proposing that propane be used only in equipment that meets
all requirements in the relevant supplements for flammable refrigerants
in certain applicable UL standards for refrigeration and AC equipment.
Specifically, Supplement SA to the 8th edition of UL 563 standard,
dated July 31, 2009, applies to self-contained commercial ice machines
using flammable refrigerants; \55\ the UL standard for water coolers
using flammable refrigerants is Supplement SB to the 7th edition of UL
399, dated August 22, 2008; \56\ and very low temperature refrigeration
equipment is sufficiently similar to stand-alone commercial
refrigerators that an appropriate standard is Supplement SB to the 10th
edition of UL 471, dated November 24, 2010.\57\
---------------------------------------------------------------------------

    \55\ UL, 2009. Standard 563--Standard for Ice Makers. A summary
of this document is accessible at: http://ulstandards.ul.com/standard/?id=563.
    \56\ UL, 2008. Standard 399--Standard for Drinking-Water
Coolers. A summary of this document is accessible at: http://ulstandards.ul.com/standard/?id=399_7.
    \57\ UL, 2010. Standard 471--Standard for Commercial
Refrigerators and Freezers. A summary of this document is accessible
at: http://ulstandards.ul.com/standard/?id=471_10.
---------------------------------------------------------------------------

    UL has tested equipment for flammability risk in household and
retail food refrigeration and for commercial freezers for very low
temperature refrigeration. Further, UL has developed acceptable safety
standards including requirements for construction, for markings, and
for performance tests concerning refrigerant leakage, ignition of
switching components, surface temperature of parts, and component
strength after being scratched. These standards were developed in an
open and consensus-based approach, with the assistance of experts in
the AC and refrigeration industry as well as experts involved in
assessing the safety of products. While similar standards exist from
other bodies such as the International Electrotechnical Commission
(IEC), we

are proposing to rely on UL standards as those that are most applicable
to and recognized by the U.S. market. This proposed approach is the
same as that adopted in our previous rules on flammable refrigerants
(76 FR 78832, December 20, 2011; 80 FR 19453, April 10, 2015).
iii. Charge Size
    EPA is proposing use conditions that limit the amount of propane
allowed in each refrigerant circuit to 150 g.\58\ It is necessary to
set limits on charge size in order for propane not to pose a risk to
human health or the environment that is greater than the risk posed by
other substitutes. These limits will reduce the risk to workers and
consumers since under scenarios we analyzed, a leak of the proposed
charge sizes did not result in concentrations of the refrigerant that
met or exceeded the LFL.
---------------------------------------------------------------------------

    \58\ To place this in context, a 150 g charge is about five
times the charge in a disposable lighter (30 g).
---------------------------------------------------------------------------

    EPA is proposing limitations on refrigerant charge size for self-
contained commercial ice machines, water coolers, and very low
temperature refrigeration equipment that reflect the UL 563, UL 399,
and UL 471 standards. As discussed above in paragraph ii of this
section, we believe UL standards are appropriate because they are the
most applicable to and recognized by the U.S. market and offer
requirements developed by a consensus of experts.
    UL Standards 563 (ice machines), 399 (water coolers), and 471
(commercial stand-alone refrigeration equipment) limit the amount of
refrigerant leaked to 150 grams (5.29 ounces). We note that the charge
size limit for propane in the UL standards is in line with the IEC
60335-2-89 standard addressing these end-uses, which also has a charge
size limit of 150 grams.
iv. Color-Coded Hoses and Piping
    EPA proposes that equipment designed for use with propane must have
distinguishing color-coded hoses and piping to indicate use of a
flammable refrigerant. This will help technicians immediately identify
the use of a flammable refrigerant, thereby reducing the risk of using
sparking equipment or otherwise having an ignition source nearby. The
AC and refrigeration industry currently uses distinguishing colors as
means to identify different refrigerants. Likewise, distinguishing
coloring has been used elsewhere to indicate an unusual and potentially
dangerous situation, for example in the use of orange-insulated wires
in hybrid electric vehicles. Currently, no industry standard exists for
color-coded hoses or pipes for propane. EPA is proposing that all such
refrigerator tubing be colored red Pantone matching system (PMS) #185
to match the red band displayed on the container of flammable
refrigerants under the Air Conditioning, Heating and Refrigeration
Institute (AHRI) Guideline ``N'' 2014, ``2014 Guideline for Assignment
of Refrigerant Container Colors.'' \59\ This proposal mirrors the
existing use condition for HCs in residential and commercial
refrigerator-freezers, vending machines, very low temperature
refrigeration equipment, non-mechanical heat transfer equipment and
room air conditioners (76 FR 78832, December 20, 2011; 80 FR 19453,
April 10, 2015). EPA wants to ensure that there is adequate notice that
a flammable refrigerant is being used within a particular piece of
equipment or appliance. One mechanism to distinguish hoses and pipes is
to add a colored plastic sleeve or cap to the service tube. The colored
plastic sleeve or cap would have to be forcibly removed in order to
access the service tube. 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) and could also be
boldly marked with a graphic to indicate the refrigerant was flammable.
This could be a cost-effective alternative to painting or dying the
hose or pipe.
---------------------------------------------------------------------------

    \59\ AHRI, 2014. Guideline N-2014 for Assignment of Refrigerant
Container Colors. This document is accessible online at http://www.ahrinet.org/App_Content/ahri/files/Guidelines/AHRI_Guideline_N_2014.pdf.
---------------------------------------------------------------------------

    EPA is particularly concerned with ensuring adequate and proper
notification for servicing and disposal of appliances containing
flammable refrigerants. The use of color-coded hoses, as well as the
use of warning labels discussed below, is necessary to ensure flammable
refrigerants can be used without presenting significantly more risk
than other alternatives and would be consistent with other general
industry practices. This proposed approach is consistent with the
approach adopted in our previous rules on flammable refrigerants (76 FR
78832, December 20, 2011; 80 FR 19453, April 10, 2015).
v. Labeling
    As a use condition, EPA is proposing to require labeling of self-
contained commercial ice machines, water coolers, and, very low
temperature refrigeration equipment. EPA is proposing the warning
labels on the equipment contain letters at least \1/4\ inch high and
that they be permanently affixed to the equipment. Warning label
language requirements are as follows:
     ``DANGER--Risk of Fire or Explosion. Flammable Refrigerant
Used. Do Not Use Mechanical Devices To Defrost Refrigerator. Do Not
Puncture Refrigerant Tubing.'' This marking must be provided on or near
any evaporators that can be contacted by the consumer.
     ``DANGER--Risk of Fire or Explosion. Flammable Refrigerant
Used. To Be Repaired Only By Trained Service Personnel. Do Not Puncture
Refrigerant Tubing.'' This marking must be located 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.''
This marking must be located near the machine compartment.
     ``CAUTION--Risk of Fire or Explosion. Dispose of Properly
In Accordance With Federal Or Local Regulations. Flammable Refrigerant
Used.'' This marking must be provided on the exterior of the
refrigeration equipment.
     CAUTION--Risk of Fire or Explosion Due To Puncture Of
Refrigerant Tubing; Follow Handling Instructions Carefully. Flammable
Refrigerant Used.'' This marking must be provided near all exposed
refrigerant tubing.
    The warning label language is similar to or exactly the same as
that required in UL standards: For commercial ice machines in UL 563 in
section SB6.1, for water coolers in UL 399 in section SA6.1, and for
commercial refrigerators and freezers, including very low temperature
freezers, in UL 471 in section SB6.1.
    It would be difficult to see warning labels with the minimum
lettering height requirement of \1/8\ inch in these UL standards.
Therefore, as in the requirements in our previous HC refrigerants rules
for residential and commercial refrigerator-freezers, vending machines,
very low temperature refrigeration equipment, non-mechanical heat
transfer equipment, and room air conditioners (76 FR 78832, December
20, 2011; 80 FR 19453, April 10, 2015), EPA is proposing the minimum
height for lettering must be \1/4\ inch as opposed to \1/8\ inch, which
will make it easier for technicians, consumers, retail storeowners, and
first responders to view the warning labels.

d. What recommendations does EPA have for the safe use of propane?
    In addition to establishing regulatory use conditions, which are
binding on end users, EPA may also make recommendations for use of a
substitute. EPA is proposing to recommend that only technicians
specifically trained in handling flammable refrigerant substitutes
dispose of or service refrigeration and AC equipment containing these
substances. Trained technicians should know how to minimize the risk of
fire and the procedures for using flammable refrigerant substitutes
safely. Releases of large quantities of flammable refrigerants during
servicing and manufacturing, especially in enclosed, poorly ventilated
spaces or in areas where large amounts of refrigerant are stored, could
cause an explosion if an ignition source exists nearby. For these
reasons, technicians should be properly trained to handle flammable
refrigerant substitutes when maintaining, servicing, repairing, or
disposing of water coolers, commercial ice machines, and very low
temperature freezers. In addition, EPA recommends that if propane would
be vented, released, or disposed of (rather than recovered), as is
proposed for the specified end-uses in this rule, the release should be
in a well-ventilated area, such as outside of a building. Ensuring
proper ventilation and avoiding ignition sources are recommended
practices, whether venting or recovering a flammable refrigerant.
    The Australian Institute of Refrigeration, Air Conditioning and
Heating (AIRAH) provides useful guidance on safety precautions
technicians can follow when servicing equipment containing flammable
refrigerants or when venting refrigerant. One of those practices is to
connect a hose to the appliance to allow for venting the refrigerant
outside.\60\ This document is included in the docket for this proposed
rule (EPA-HQ-OAR-2015-0663).
---------------------------------------------------------------------------

    \60\ AIRAH, 2013. Australian Institute of Refrigeration, Air
Conditioning and Heating. Safety Guide: Flammable Refrigerants.
2013. This document is accessible at: http://www.unep.fr/ozonaction/information/mmcfiles/7681-e-FlammableRefrigerantsGuideAIRAH.pdf.
---------------------------------------------------------------------------

    We are aware that at least two organizations in the United States,
Refrigeration Service Engineers Society (RSES) and the ESCO Institute,
have developed technician training programs in collaboration with
refrigeration equipment manufacturers and users that address safe use
of flammable refrigerant substitutes. In addition, EPA has reviewed
several training programs provided as part of SNAP submissions from
persons interested in flammable refrigerant substitutes. The agency
intends to update the test bank for technician certification under CAA
section 608 as we have done previously, and will consider including
additional questions on flammable refrigerants. By adding such
questions to the test bank, EPA would supplement but would not replace
technician training programs currently provided by non-government
entities. EPA will seek additional information and guidance on how best
to incorporate this content through a separate process outside the
scope of this final rule.
e. When would the listing apply?
    EPA proposes that this listing would apply 30 days after the date
of publication of a final rule. This date, the same as the proposed
effective date of this regulation, allows for the safe use of this
substitute at the earliest opportunity.
f. What is the relationship between this proposed SNAP rule and other
federal rules?
i. How would this proposed listing relate to federal energy
conservation standards?
    For some of the types of equipment covered in this proposal, DOE
has established energy conservation standards. For example, DOE energy
conservation standards apply to automatic commercial ice machines.\61\
Thus, total energy use with propane can be expected to be no higher
than that required by the standards for those classes of equipment.\62\
DOE does not have an energy conservation standard that would apply to
water coolers or to very low temperature refrigeration equipment. EPA
considers technical needs for energy efficiency (e.g., to meet DOE
energy conservation standards) in determining whether alternatives are
``available.'' Based on available information, we found no evidence
that propane would reduce energy efficiency or that equipment using
propane would be unable to meet DOE energy efficiency standards in the
end-uses proposed in this rule, and we found some evidence that propane
may improve energy efficiency.63 64 65
---------------------------------------------------------------------------

    \61\ See https://www1.eere.energy.gov/buildings/appliance_standards/standards_test_procedures.html.
    \62\ Refrigeration or AC equipment in the applicable covered
equipment class would still be subject to DOE's standards,
regardless of the refrigerant that the equipment uses. If a
manufacturer believes that its design is subjected to undue hardship
by DOE's regulations, the manufacturer may petition DOE's Office of
Hearing and Appeals (OHA) for exception relief or exemption from the
standard pursuant to OHA's authority under section 504 of the DOE
Organization Act (42 U.S.C. 7194), as implemented at subpart B of 10
CFR part 1003. OHA has the authority to grant such relief on a case-
by-case basis if it determines that a manufacturer has demonstrated
that meeting the standard would cause hardship, inequity, or unfair
distribution of burdens.
    \63\ Eppendorf, 2015. SNAP Information Notice for R-170 and R-
290 in Very Low Temperature Refrigeration. May, 2015.
    \64\ Manitowoc, 2015. SNAP Information Notice, September, 2013.
EPA SNAP Submittal--Revision to Extend R-290 Use to Commercial Ice
Machines, Manitowoc Ice, Inc. October, 2015.
    \65\ Blupura, 2015. SNAP Information Notice for R-290 in Water
Coolers. October, 2015.
---------------------------------------------------------------------------

ii. How would this proposed listing relate to regulations implementing
the venting prohibition under CAA section 608?
    Below in section VI.A.2 of this document, EPA is proposing to
exempt propane from the venting prohibition under CAA section 608 when
propane is used as a refrigerant in self-contained commercial ice
machines, water coolers, or very low temperature refrigeration
equipment.
g. On which topics is EPA specifically requesting comment?
    EPA requests comment on all aspects of the proposed listing of
propane as an acceptable refrigerant in self-contained commercial ice
machines, water coolers, and very low temperature refrigeration
equipment, including the proposed use conditions discussed in section
VI.A.1.c. We request comment on our risk screens and the assumptions
and exposure and flammability levels EPA used to evaluate risk. We are
particularly interested in comment of two of the proposed use
conditions: (1) The use of red marking for pipes, hoses and other
devices including direct color application on the applicable parts of
the system, such as a red plastic sleeve (see section VI.A.1.c.iv,
``Color-coded hoses and piping''); and (2) the UL standards that EPA
proposes to incorporate by reference (i.e., Supplement SA to the 8th
edition of UL 563, dated July 31, 2009, for self-contained commercial
ice machines, Supplement SB to the 7th edition of UL 399, dated August
22, 2008, for water coolers; and Supplement SB to the 10th edition of
UL 471, dated November 24, 2010, for very low temperature refrigeration
equipment.

2. Proposed Exemption for Propane From the Venting Prohibition Under
CAA Section 608 for the End-Uses in the Proposed New SNAP Listing
a. What is EPA's proposal regarding whether venting of propane in the
end-uses in this action would pose a threat to the environment?
    EPA is proposing to list the refrigerant substitute propane under
the SNAP program as acceptable, subject to use conditions, in newly
manufactured water coolers, self-contained commercial ice machines, and
very low temperature refrigeration equipment. EPA is also proposing to
exempt propane in these end-uses from the venting prohibition under CAA
section 608(c)(2). For purposes of CAA section 608(c)(2), EPA considers
two factors in determining whether or not venting, release, or disposal
of a refrigerant substitute during the maintenance, servicing,
repairing, or disposing of appliances poses a threat to the
environment. See 69 FR 11948, March 12, 2004; 79 FR 29682, May 23,
2014; and 80 FR 19453, April 10, 2015. First, EPA analyzes the threat
to the environment due to inherent characteristics of the refrigerant
substitute, such as GWP. Second, EPA determines whether and to what
extent venting, release, or disposal actually takes place during the
maintenance, servicing, repairing, or disposing of appliances, and to
what extent such actions are controlled by other authorities,
regulations, or practices. To the extent that such releases are
adequately controlled by other authorities, EPA defers to those
authorities.
i. Potential Environmental Impacts
    EPA has evaluated the potential environmental impacts of releasing
into the environment propane, the substitute that we are proposing to
list under the SNAP program as acceptable, subject to use conditions,
in water coolers, self-contained commercial ice machines, and very low
temperature refrigeration equipment. In particular, we assessed the
potential impact of the release of propane on local air quality and its
ability to decompose in the atmosphere, its ODP, its GWP, and its
potential impacts on ecosystems.
    As explained above in section VI.A.1.b.i, ``Environmental
impacts,'' propane's ODP is zero, its GWP is approximately three, and
its effects on aquatic life are expected to be small. As to potential
effects on local air quality, based on the analysis and modeling
results described in section VI.A.1.b.i of this preamble, EPA proposes
to conclude that release of propane from the end-uses proposed in this
action, in addition to the HCs previously listed as acceptable, subject
to use conditions, for their specific end-uses, is expected to have
little impact on local air quality. In this regard, EPA finds
particularly noteworthy that even assuming 100 percent market
penetration of propane and the other acceptable HCs in the proposed and
acceptable end-uses, which is a conservative assumption, the highest
impact for a single 8-hour average concentration based on this analysis
would be 0.03 ppb in Los Angeles.
    In addition, when examining all HC substitute refrigerants in those
uses for which UL currently has standards in place, for which the SNAP
program has already listed the uses as acceptable, subject to use
conditions, or for which the SNAP program is reviewing a submission,
including those in this rule, we found that even if all the refrigerant
in appliances in end-uses proposed as acceptable, subject to use
conditions in this proposed rule and listed as acceptable in previous
rules were to be emitted, there would be a worst-case impact of less
than 0.15 ppb for ground-level ozone in the Los Angeles area.\66\ The
use conditions established in the SNAP listings limit the total amount
of refrigerant in each refrigerant circuit to 150 g or less, depending
on the end-use. Because propane is not proposed to be used in all
refrigerant uses, the total amount of propane that could be emitted in
the end-uses evaluated is estimated at roughly ten percent of total
refrigerant emissions, or less than 16,000 metric tons annually.\67\
Further, there are other substitute refrigerants that are not VOC that
may also be used in these end-uses, so our analysis assuming complete
market penetration of HCs is conservative. In light of its evaluation
of potential environmental impacts, EPA proposes that propane in the
end-uses for which it is proposed to be listed under SNAP as
acceptable, subject to use conditions, in this notice is not expected
to pose a threat to the environment on the basis of the inherent
characteristics of this substance and the limited quantities used in
the relevant end-uses. In this regard, EPA finds particularly
noteworthy that even assuming 100% market penetration of propane and
the other acceptable HCs in the proposed and acceptable end-uses, which
is a conservative assumption, the highest impact for a single 8-hour
average concentration based on this analysis would be 0.03 ppb in Los
Angeles.
---------------------------------------------------------------------------

    \66\ ICF, 2014a. Assessment of the Potential Impact of
Hydrocarbon Refrigerants on Ground Level Ozone Concentrations.
February, 2014.
    \67\ Ibid.
---------------------------------------------------------------------------

ii. Flammability and Toxicity
    As discussed above in sections VI.A.1.b.ii, ``Flammability'' and
VI.A.1.b.iii, ``Toxicity,'' EPA's SNAP program evaluated the
flammability and toxicity risks from propane in the proposed end-uses
in this rule. EPA is providing some of that information in this section
as well.
    Propane is classified as an A3 refrigerant by ASHRAE Standard 34-
2010 and subsequent addenda, indicating that it has low toxicity and
high flammability. Propane has an LFL of 2.1%. To address flammability
risks, this proposal provides recommendations for its safe use (see
section VI.A.1.d, ``What recommendations does EPA have for the safe use
of propane?'' above). The SNAP program's analysis suggests that the
proposed use conditions in this proposed rule will mitigate
flammability risks.
    Like most refrigerants, at high concentrations HCs can displace
oxygen and cause asphyxiation. Various industry and regulatory
standards exist to address asphyxiation and toxicity risks. The SNAP
program's analysis of asphyxiation and toxicity risks suggests that the
proposed use conditions in this proposed rule would mitigate
asphyxiation and toxicity risks. Furthermore, it is the Agency's
understanding that flammability risks and occupational exposures to HCs
are adequately regulated by OSHA and building and fire codes at a local
and national level.
iii. Authorities, Controls, or Practices
    EPA expects that existing authorities, controls, and/or practices
will mitigate environmental risk from the release of propane. Analyses
performed for both this proposed rule and the SNAP rules issued in
1994, 2011, and 2015 (59 FR 13044, March 17, 1994; 76 FR 38832,
December 20, 2011; and 80 FR 19453, April 10, 2015, respectively))
indicate that existing regulatory requirements and industry practices
limit and control the emission of propane. As explained below, EPA
proposes that the limits and controls under other authorities,
regulations, or practices adequately control the release of and
exposure to propane and mitigate risks from any possible release.
    As mentioned above, the determination of whether venting, release,
or disposal of a substitute refrigerant poses a threat to the
environment includes considering

whether such venting, release, or disposal is adequately controlled by
other authorities, regulations, or practices. This information is
another part of EPA's proposal that the venting, release, or disposal
of propane, in the specified end-uses and subject to the use conditions
in this proposed action, does not pose a threat to the environment.
    Industry service practices and OSHA standards and guidelines that
address HC refrigeration equipment include monitoring efforts,
engineering controls, and operating procedures. OSHA requirements that
apply during servicing include continuous monitoring of explosive gas
concentrations and oxygen levels. In general, HC emissions from
refrigeration systems are likely to be significantly smaller than those
emanating from the industrial process and storage systems, which are
controlled for safety reasons. In the SNAP listings in section
VI.A.1.c, ``What are the proposed use conditions?'' we note that the
amount of refrigerant substitute from a refrigerant loop is limited to
150 g in the end-uses proposed in this rule. This indicates that HC
emissions from such uses are likely to be relatively small.
    The release and/or disposal of many refrigerant substitutes,
including propane, are controlled by other authorities including
various standards, and state and local building codes. To the extent
that release during maintaining, repairing, servicing, or disposing of
appliances is controlled by regulations and standards of other
authorities, these practices and controls for the use of propane are
sufficiently protective. These practices and controls mitigate the risk
to the environment that may be posed by the venting, release, or
disposal of propane during the maintaining, servicing, repairing, or
disposing of appliances.
    EPA is aware of equipment that can be used to recover HC
refrigerants. While there are no relevant U.S. standards for such
recovery equipment currently, to the extent that propane is recovered
rather than vented in specific end-uses and equipment, EPA recommends
the use of recovery equipment designed specifically for flammable
refrigerants in accordance with applicable safe handling practices. See
section VI.A.1.d above, ``What recommendations does EPA have for the
safe use of propane?''
b. What is EPA's proposal regarding whether venting of propane in the
end-uses in this action should be exempted from the venting prohibition
under CAA section 608?
    Consistent with the proposed listing under SNAP in this action, EPA
proposes that venting, releasing or disposing of propane in water
coolers, self-contained commercial ice machines, and very low
temperature refrigeration equipment is not expected to pose a threat to
the environment. As discussed more fully above, we propose this on the
basis of the inherent characteristics of this substance, the limited
quantities used in the relevant end-uses, and the limits and controls
under other authorities, regulations, or practices that adequately
control the release of and exposure to propane and mitigate risks from
any possible release. Accordingly, EPA is proposing to revise the
regulations at Sec.  82.154(a)(1) to add propane in these end-uses to
the list of substitute refrigerants that are exempt from the venting
prohibition. We also note that EPA has recently proposed to revise the
format of the text of this section to include separate paragraphs for
each substitute refrigerant, rather than grouping refrigerants in an
end-use (80 FR 69457; November 9, 2015). Thus, the final text of Sec.
82.154(a)(1) may reflect revised language related to both the November
2015 proposal and to this proposal.
c. When would the exemption from the venting prohibition apply?
    We are proposing that propane would be exempt from the venting
prohibition as of 30 days after the publication of a final rule in the
Federal Register. This would be the same as the date of the SNAP
listing of propane in commercial ice machines, water coolers, and very
low temperature refrigeration equipment.
d. What is the relationship between this proposed exemption under CAA
section 608 and other EPA rules?
    If this proposed exemption were to become final as proposed, it
would not mean that propane could be vented in all situations. Propane
and other HCs being recovered, vented, released, or otherwise disposed
of from commercial and industrial appliances are likely to be hazardous
waste under RCRA (see 40 CFR parts 261 through 270). As discussed in
the final rules addressing the venting of ethane, isobutane, propane,
and R-441A as refrigerant substitutes in certain end-uses, incidental
releases may occur during the maintenance, service, and repair of
appliances subject to CAA section 608 (79 FR 29682, May 23, 2014; 80 FR
19454, April 10, 2015). Such incidental releases would not be subject
to RCRA requirements for the disposal of hazardous waste, as such
releases would not constitute disposal of the refrigerant charge as a
solid waste, per se. Disposal or venting of propane from household
appliances used in the home, such as a water cooler, is also generally
not considered disposal of a hazardous waste under the existing RCRA
regulations and could be vented under the household hazardous waste
exemption, assuming other state or local requirements do not prohibit
venting. See 40 CFR 261.4(b)(1). However, for commercial and industrial
appliances such as self-contained commercial ice machines, very low
temperature refrigeration equipment, or water coolers used in an
industrial or office setting, it is likely that propane and other
flammable HC refrigerant substitutes would be classified as hazardous
waste and disposal of propane from such appliances would need to be
managed as hazardous waste under the RCRA regulations (40 CFR parts 261
through 270), unless it is subject to a limited exception in those
regulations if the ignitable refrigerant is to be recycled.
e. On which topics is EPA specifically requesting comment?
    EPA requests comment on all aspects of our proposal to exempt from
CAA section 608's venting prohibition the venting or release of propane
used as a refrigerant substitute in water coolers, self-contained
commercial ice machines, and very low temperature refrigeration
equipment, as well as seeking comment on the proposed exemption
language at 40 CFR 82.154(a)(1).
3. Proposed Listing of New Refrigerants as Unacceptable
a. Proposed Listing of Certain Flammable Refrigerants as Unacceptable
for Retrofits in Unitary Split AC Systems and Heat Pumps
    EPA is proposing to list the following flammable refrigerants as
unacceptable for use in existing unitary split AC and heat pumps for
residential and light commercial AC and heat pumps because they pose
significantly more risk to human health or the environment than other
available alternatives:
     All refrigerants identified as flammability Class 3 in
ANSI/ASHRAE Standard 34-2013.
     All refrigerants meeting the criteria for flammability
Class 3 in ANSI/

ASHRAE Standard 34-2013. These include, but are not limited to,
refrigerant products sold under the names R-22a, 22a, Blue Sky 22a
refrigerant, Coolant Express 22a, DURACOOL-22a, EC-22, Ecofreeeze 22a,
EF-22a, Envirosafe 22a, ES-22a, Frost 22a, HC-22a, Maxi-Fridge, MX-22a,
Oz-Chill 22a, Priority Cool, and RED TEK 22a.
    Existing unitary split AC systems and heat pumps were not designed
to use a flammable refrigerant. We are aware of instances in which
people or property have been harmed by retrofit or so-called `drop-in'
use of certain of the specified flammable refrigerants in equipment
designed to use HCFC-22. For new equipment, we have listed certain
flammable refrigerants as acceptable on the basis that flammability
risks can be addressed in designing the equipment and mitigated through
use conditions. In contrast, existing equipment has not been designed
for flammable refrigerants and we have not identified appropriate use
conditions that can manage the flammability risk for retrofits such
that these flammable refrigerants would pose similar or lower risk than
other available refrigerants in this end-use.
i. What is the affected end-use?
    The residential and light commercial AC and heat pumps end-use
includes equipment for cooling air in individual rooms, in single-
family homes, and sometimes in small commercial buildings. This end-use
differs from commercial comfort AC, which uses chillers that cool water
that is then used to cool air throughout a large commercial building,
such as an office building or hotel. This proposal specifically
concerns unitary split systems and heat pumps, commonly called central
AC. These systems include an outdoor unit with a condenser and a
compressor, refrigerant lines, an indoor unit with an evaporator, and
ducts to carry cooled air throughout a building. Central heat pumps are
similar but offer the choice to either heat or cool the indoor space.
We are proposing that certain flammable refrigerants would be listed as
unacceptable for retrofit use in this type of equipment.
    We are not currently proposing that the unacceptability
determination for certain flammable refrigerants applies to other types
of residential AC and heat pump equipment, but we may do so in the
future. The presence of a proposal for a single type of equipment
within this end-use or listings finding certain substitutes acceptable,
subject to use conditions, in a specific type of equipment does not
imply that other uses are acceptable (e.g., listing as acceptable,
subject to use conditions in new equipment does not mean retrofit use
is acceptable). Other types of residential AC and heat pump equipment
not included in this proposed unacceptability determination include:
     Multi-split air conditioners and heat pumps. These systems
include one or more outdoor unit(s) with a condenser and a compressor
and multiple indoor units, each of which is connected to the outdoor
unit by refrigerant lines. For ductless multi-split systems, the cooled
air exits directly from the indoor unit rather than being carried
through ducts.
     Mini-split air conditioners and heat pumps. These systems
include an outdoor unit with a condenser and a compressor and a single
indoor unit that is connected to the outdoor unit by refrigerant lines.
Cooled air exits directly from the indoor unit rather than being
carried through ducts.
     Packaged outdoor air conditioners and heat pumps. These
systems include an outdoor unit with a condenser and a compressor and a
heating assembly, often used on top of the roof of a building such as a
commercial office building or apartment building. These units carry
cool air to the inside of the building through ducts, so they are not
completely self-contained units; however, the refrigerant remains
within the packaged unit, thus reducing the chance of leaks from
refrigerant lines.
     Window air conditioners and heat pumps. These are self-
contained units that fit in a window with the condenser extending
outside the window.
     Packaged terminal air conditioners (PTACs) and packaged
terminal heat pumps (PTHP). These are self-contained units that consist
of a separate, un-encased combination of heating and cooling assemblies
mounted through a wall.
     Portable room air conditioners and heat pumps. These are
self-contained, factory-sealed, single package units that are designed
to be moved easily from room to room and are intended to provide
supplemental cooling within a room. These units typically have wheels
or casters for portability and have a fan which operates continuously
when the unit is on. Portable room air conditioners and heat pumps may
contain an exhaust hose that can be placed through a window or door to
eject heat to the outside.
    Compared to self-contained AC equipment such as window air
conditioners, PTAC, PTHP, and portable room air conditioners, unitary
split AC systems and heat pumps are much more likely to have a
refrigerant release due to having larger charge sizes, more locations
that are prone to leak, and because they are more likely to require
servicing by a technician. A higher risk of refrigerant releases and a
potential for larger releases and higher concentration releases results
in higher risk that flammable refrigerant could be ignited from unitary
split AC systems and heat pumps compared to self-contained equipment.
    EPA is aware of a number of situations where companies have sold
highly flammable refrigerants for use in residential AC that have not
been submitted to SNAP for review. EPA has conducted enforcement
actions against companies that have sold such substitutes in violation
of EPA's regulations.\68\ EPA is aware of multiple cases, where people
and property using the ``22a'' refrigerant in a residential AC system
were harmed in explosions and fires, in part because the person
servicing the AC system was not aware that the system contained a
highly flammable refrigerant. Considering this demonstration of the
flammability risks of retrofitting residential AC systems as well as
the lack of risk mitigation available for existing equipment (e.g.,
charge limits, design for reduced leakage), EPA is proposing to list R-
22a, 22a, and other similar liquified petroleum gases as unacceptable,
as well as refrigerants with a flammability classification of 3 in
ASHRAE 34-2013.
---------------------------------------------------------------------------

    \68\ EPA, 2013. Finding of Violation, issued to Enviro-Safe
Refrigerants, Inc. June, 2013. This document is accessible at:
http://www2.epa.gov/sites/production/files/2015-07/documents/mailfov_envirosafe_06112013.pdf.
---------------------------------------------------------------------------

ii. Which refrigerants is EPA proposing to list as unacceptable?
    EPA is proposing that the following flammable refrigerants be
listed as unacceptable for retrofits in unitary split AC systems and
heat pumps:
     All refrigerants identified as flammability Class 3 in
ANSI/ASHRAE Standard 34-2013.
     All refrigerants meeting the criteria for flammability
Class 3 in ANSI/ASHRAE Standard 34-2013. These include, but are not
limited to, refrigerant products sold under the names R-22a, 22a, Blue
Sky 22a refrigerant, Coolant Express 22a, DURACOOL-22a, EC-22,
Ecofreeeze 22a, EF-22a, Envirosafe 22a, ES-22a, Frost 22a, HC-22a,
Maxi-Fridge, MX-22a, Oz-Chill 22a, Priority Cool, and RED TEK 22a.
    ANSI/ASHRAE Standard 34-2013 assigns a safety group classification
for each refrigerant which consists of two

alphanumeric characters (e.g., A2 or B1). The capital letter indicates
the toxicity and the numeral denotes the flammability. ASHRAE
classifies Class A refrigerants as refrigerants for which toxicity has
not been identified at concentrations less than or equal to 400 parts
per million (ppm) by volume, based on data used to determine TLV-TWA or
consistent indices. Class B signifies refrigerants for which there is
evidence of toxicity at concentrations below 400 ppm by volume, based
on data used to determine TLV-TWA or consistent indices. The
refrigerants are also assigned a flammability classification of 1, 2,
or 3. Tests are conducted in accordance with ASTM E681 using a spark
ignition source at 60 [deg]C and 101.3 kPa.\69\ Figure 1 in ANSI/ASHRAE
Standard 15-2013 uses the same safety group but limits its
concentration to 3,400 ppm.\70\
---------------------------------------------------------------------------

    \69\ ASHRAE, 2013. ANSI/ASHRAE Standard 34-2013: Designation and
Safety Classification of Refrigerants.
    \70\ ASHRAE, 2013. ANSI/ASHRAE Standard 15-2013: Designation and
Safety Classification of Refrigerants.
---------------------------------------------------------------------------

    The flammability classification ``1'' is given to refrigerants
that, when tested, show no flame propagation. The flammability
classification ``2'' is given to refrigerants that, when tested,
exhibit flame propagation, have a heat of combustion less than 19,000
kJ/kg (8,174 British thermal units (BTU)/lb), and have a LFL greater
than 0.10 kg/m\3\. Refrigerants within flammability classification 2
may optionally be designated in the LFL subclass ``2L'' if they have a
maximum burning velocity of 10 cm/s or lower when tested at 23.0 [deg]C
and 101.3 kPa. The flammability classification ``3'' is given to
refrigerants that, when tested, exhibit flame propagation and that
either have a heat of combustion of 19,000 kJ/kg (8,174 BTU/lb) or
greater or an LFL of 0.10 kg/m\3\ or lower. Thus, refrigerants with
flammability classification ``3'' are highly flammable while those with
flammability classification ``2'' are less flammable and those with
flammability classification ``2L'' are mildly flammable. For both
toxicity and flammability classifications, refrigerant blends are
designated based on the worst-case of fractionation determined for the
blend (which may be different when evaluating toxicity than when
evaluating flammability).
[GRAPHIC] [TIFF OMITTED] TP18AP16.001

    Refrigerants with a flammability classification of 3 identified by
ASHRAE in ASHRAE 34-2013 include the HCs R-1150 (ethylene), R-170
(ethane), R-1270 (propylene), R-290 (propane), R-50 (CH4),
R-600 (n-butane), R-600a (isobutane), R-601 (n-pentane), and R-601a
(isopentane); the HC blends R-433A, R-433B, R-433C, R-436A, R-436B, R-
441A, and R-443A; and the refrigerant blends R-429A, R-430A, R-431A, R-
432A, R-435A, and R-511A. All but one of these refrigerants contain
HCs, with some also containing the flammable compounds dimethyl ether
and HFC-152a.
    In addition to refrigerants specifically identified in the ASHRAE
34-2013 standard as having a flammability classification of 3, EPA is
proposing that refrigerants meeting the criteria of that standard are
unacceptable. In other words, refrigerants are unacceptable if they
exhibit flame propagation and either have a heat of combustion of
19,000 kJ/kg (8,174 BTU/lb) or greater or an LFL of 0.10 kg/m\3\ or
lower, when tested in accordance with ASTM E681 using a spark ignition
source at 60 [deg]C and 101.3 kPa. We are aware of a number of
refrigerant products sold over the internet aimed at the market for
retrofit usage in refrigeration and AC equipment using HCFC-22 with
names containing ``22a,'' such as R-22a, Blue Sky 22a refrigerant,
Coolant Express 22a, DURACOOL-22a, EC-22, Ecofreeeze 22a, EF-22a,
Envirosafe 22a, ES-22a, Frost 22a, HC-22a, Maxi-Fridge, MX-22a, Oz-
Chill 22a, and RED TEK 22a. EPA has analyzed one of these refrigerants
and determined that it contained propane mixed with a pine-scented
odorant. These refrigerants are also identified as flammable in their
Safety Data Sheets and are often identified as ``liquified petroleum
gases.'' Although none of these liquified petroleum gas refrigerants
have been submitted to SNAP for review, EPA expects that they all are
comparable in their flammability to propane and other refrigerants that
meet an ASHRAE flammability classification of 3. It is our
understanding these refrigerants are all of the same or similar
composition, are produced by only one or two facilities using the same
process, and then are marketed under different names.
    We request comment on whether we should list as unacceptable both
any refrigerant that meets the criteria in ASHRAE 34-2013 for a
flammability

classification of 3 and those refrigerants currently identified in the
ASHRAE standard with a flammability classification of 3. We also
request comment on whether the listing decision should specifically
describe the criteria, i.e., ``Any refrigerant that (1) exhibits flame
propagation when tested by ASTM E681 at standard temperature and
pressure and at 60 [deg]C and (2) that either has a heat of combustion
of 19,000 kJ/kg (8,174 BTU/lb) or greater or has an LFL of 0.10 kg/m\3\
or lower.''
ii. How do these proposed unacceptable refrigerants compare to other
refrigerants for these end-uses with respect to SNAP criteria?
    The SNAP program considers a number of environmental criteria when
evaluating substitutes: ODP; climate effects, primarily based on GWP;
local air quality impacts, particularly potential impacts on smog
formation from emissions of VOC; ecosystem effects, particularly from
negative impacts on aquatic life. These and other environmental and
health risks (e.g., flammability, exposure, and toxicity) are discussed
below. In addition, a technical support document \71\ that provides the
Federal Register citations concerning data on the SNAP criteria (e.g.,
ODP, GWP, VOC, toxicity, flammability) for acceptable alternatives in
the relevant end-uses may be found in the docket for this rulemaking
(EPA-HQ-OAR-2015-0663).
---------------------------------------------------------------------------

    \71\ EPA, 2016b. Draft Tables of Alternatives for End-Uses
Considered in the Notice of Proposed Rule Making, Protection of
Stratospheric Ozone: Listing Modifications for Certain Substitutes
under the Significant New Alternatives Policy Program. March, 2016.
---------------------------------------------------------------------------

(a) Environmental Impacts
    EPA has listed a number of alternatives as acceptable for retrofit
usage in unitary split AC systems and heat pumps. All of the listed
alternatives are HFC blends, with some containing small percentages
(approximately five percent or less) of HCs. Specific blends include:
R-125/134a/600a (28.1/70/1.9), R-125/290/134a/600a (55.0/1.0/42.5/1.5),
R-404A, R-407C, R-407F, R-417A, R-417C, R-421A, R-422B, R-422C, R-422D,
R-424A, R-427A, R-434A, R-438A, R-507A, and RS-44 (2003 composition).
These blends are all non-ozone-depleting. As shown in Table 3, they
have GWPs ranging from approximately 1,770 for R-407C to 3,990 for R-
507A. Knowingly venting or releasing these refrigerants is limited by
the venting prohibition under section 608(c)(2) of the CAA, codified at
40 CFR 82.154(a)(1). The HFC components of these refrigerant blends are
excluded from the definition of VOC under CAA regulations (see 40 CFR
51.100(s)) addressing the development of SIPs to attain and maintain
the NAAQS, while the HC components are VOC.

   Table 3--GWP, ODP, and VOC Status of Flammable Refrigerants Compared to Other Refrigerants for Retrofit in
  Existing Equipment for Residential and Light Commercial AC (Unitary Split AC Systems and Heat Pumps) 1 2 3 4
----------------------------------------------------------------------------------------------------------------
           Refrigerants                   GWP             ODP                VOC                  Proposal
----------------------------------------------------------------------------------------------------------------
All refrigerants identified as               2-120               0  Yes \3\..............  Unacceptable.
 flammability Class 3 in ANSI/
 ASHRAE Standard 34-2013.
All refrigerants meeting the                 2-120               0  Yes \3\..............  Unacceptable.
 criteria for flammability Class 3
 in ANSI/ASHRAE Standard 34-2013,
 including, but not limited \1\,
 to the products named R-22a, 22a,
 Blue Sky22a refrigerant, Coolant
 Express 22a, DURACOOL-22a, EC-22,
 Ecofreeeze EF-22a, EF-22a,
 Envirosafe 22a, ES-22, Frost 22a,
 HC-22a, Maxi-Fridge, MX-22a, OZ-
 Chill 22a, Priority Cool, and RED
 TEK22a.
R-404A, R-407A, R-407C, R-407F, R-     1,770-3,990               0  No...................  No change.
 421A, R-427A, R-507A.
Hot Shot 2, R-125/R-134a/R-600a        1,810-3,390               0  Yes \4\..............  No change.
 (28.1/70.0/1.9), R-125/R-290/R-
 134a/R-600a (55.0/1.0/42.5/1.5),
 R-417A, R-422B, R-422C, R-422D, R-
 424A, R-427A, R-434A, R-437A, R-
 438A, RS-44 (2003 formulation).
----------------------------------------------------------------------------------------------------------------
\1\ The table does not include not-in-kind technologies listed as acceptable for the stated end-use.
\2\ HCFC-22 and several blends containing HCFCs are also listed as acceptable but their use is severely
  restricted by the phasedown in HCFC production and consumption.
\3\ The entire refrigerant or most of the constituents are VOC.
\4\ One or more constituents of the refrigerant are VOC.

    Both the currently acceptable refrigerants and those proposed to be
unacceptable are non-ozone depleting. The refrigerants proposed to be
unacceptable would result in higher VOC emissions than the acceptable
refrigerants, with the saturated HCs (e.g., propane, isobutane) having
a low impact and unsaturated HCs (e.g., propylene) having a significant
impact (see section VI.A.1.b.i above. The refrigerants proposed to be
unacceptable have significantly lower GWPs than the refrigerants that
would remain acceptable.
(b) Flammability
    All refrigerants currently listed as acceptable in this end-use are
nonflammable, resulting in no risk of fire or explosion from
flammability of the refrigerant. In comparison, ASHRAE Class 3
refrigerants are highly flammable. As discussed further below in
section VI.A.3.b.iii.(b), EPA analyzed the flammability impacts of one
ASHRAE Class 3 refrigerant, R-443A, and found that a release of the
entire refrigerant charge inside a building from a unitary split AC
system or heat pump could result in surpassing the LFL.\72\ Because of
the large charge sizes required for this type of equipment and the
similar LFLs for other ASHRAE Class 3 refrigerants, it is likely the
LFL would be surpassed for other ASHRAE Class 3 refrigerants. Fires and
harm to

people and property have already occurred in multiple cases due to
retrofit or drop-in use of R-22a and similar products in existing
unitary split AC systems.
---------------------------------------------------------------------------

    \72\ ICF, 2016f. Significant New Alternatives Policy Program.
Refrigeration and Air Conditioning Sector Risk Screen on Substitutes
in Residential and Light Commercial Air Conditioning and Heat Pumps.
Substitute: R-443A.
---------------------------------------------------------------------------

(c) Toxicity
    The HFC components of acceptable substitutes in this end-use, as
well as the HFC components of the unacceptable refrigerant blends have
exposure limits, such as WEELs from the AIHA or manufacturer acceptable
exposure limits, of 1,000 ppm on an 8-hr TWA and the HC components of
both the acceptable refrigerants and those proposed unacceptable have
exposure limits ranging from 500 to 1,000 ppm (8-hr TWA for TLVs from
ACGIH and 10-hr TWA for recommended exposure limits (RELs) from NIOSH).
Both the acceptable refrigerants and the proposed unacceptable
refrigerants are able to be used be used in this end-use in accordance
with their respective 8-hr or 10-hr workplace exposure limits. Acute
exposure may also be of concern during use in unitary split AC systems
and heat pumps because of possible exposure to consumers in the event
of a sudden release. The currently acceptable refrigerants typically
have high acute exposure limits for their components based upon
cardiotoxic effects of halocarbons over 10,000 ppm (e.g., 350,000
cardiotoxic no-observed adverse effect level for HFC-32 over 5 minutes)
or have components with STELs or AEGLs (e.g., 8,000 ppm 10-minute AEGL-
1 for HFC-134a component). Acute exposure limits for components of the
ASHRAE Class 3 refrigerants are comparable or lower, ranging from 1,500
ppm (e.g., excursion limit for propylene) to 6,900 ppm (AEGL-1 over 30
minutes for propane). Because of the large charge sizes required for
this type of equipment and somewhat lower acute exposure limits for the
hydrocarbon components of ASHRAE Class 3 refrigerants, acute exposure
could be a concern for specific refrigerants. For example, as discussed
further below in section VI.A.3.b.iii.(c), EPA analyzed the toxicity
impacts of the propylene component of R-443A, and found that a
catastrophic leak of that refrigerant inside a building from a unitary
split AC system or heat pump resulted in estimated exposure levels at
least four-fold that of the 1,500 ppm acute exposure limit.\73\
---------------------------------------------------------------------------

    \73\ Ibid.
---------------------------------------------------------------------------

    At this time, the potential reduced climate risks from using a
highly flammable refrigerant with lower GWP does not outweigh the
flammability risks of using these refrigerants in existing equipment
that was designed for nonflammable refrigerants. In addition to
flammability risk, in at least some cases, acute exposure limits of the
proposed unacceptable refrigerants may be more difficult to attain than
those for acceptable refrigerants in this end-use. Therefore, EPA
proposes that the highly flammable refrigerants proposed to be
unacceptable pose greater overall risk to human health and the
environment than other substitutes for retrofit in the residential and
light commercial AC and heat pumps end-use. However, the Agency may
look back at these end-uses for other reasons if we receive information
on how risks from the refrigerants proposed for listing as unacceptable
can be sufficiently mitigated, we may reconsider any final action
listing these refrigerants as unacceptable in this end use.
iv. When would the listings apply?
    EPA proposes that these listings would apply 30 days after the date
of publication of a final rule. To date, only one of these substitutes
have been submitted to EPA for this end-use and this submission is
currently incomplete. Thus, under 40 CFR 82.174, manufacturers are
prohibited from introducing them into interstate commerce for this end-
use. Thus, manufacturers and service technicians should not be
currently using these substitutes in the manner that would be
prohibited by this proposed listing decision. Further, a date or 30
days after the date of publication of a final rule, the same as the
proposed effective date of this regulation, would protect technicians
and consumers from the risks of these substitutes at the earliest
opportunity.
v. What is the relationship between this proposed SNAP rule and other
federal rules?
    EPA is not aware of other federal rules that would apply to the use
of these flammable refrigerants for retrofits in existing unitary split
AC systems and heat pumps.
vi. On which topics is EPA specifically requesting comment?
    EPA requests comment on all aspects of this proposal. In
particular, we request comment on our proposal to list as unacceptable
for retrofit use in existing unitary split AC systems and heat pumps
all refrigerants identified as flammability Class 3 in ANSI/ASHRAE
Standard 34-2013 and all refrigerants meeting the criteria for
flammability Class 3 in ANSI/ASHRAE Standard 34-2013, including, but
not limited to, refrigerant products sold under the names R-22a, 22a,
Blue Sky 22a refrigerant, Coolant Express 22a, DURACOOL-22a, EC-22,
Ecofreeeze 22a, EF-22a, Envirosafe 22a, ES-22a, Frost 22a, HC-22a,
Maxi-Fridge, MX-22a, Oz-Chill 22a, Priority Cool, and RED TEK 22a. The
agency also requests comment on the proposed decision to list these
substitutes as unacceptable 30 days after the date of publication of a
final rule, and any additional technical information on how risks from
the refrigerants proposed for listing as unacceptable can be
sufficiently mitigated.
b. Proposed Listing of Propylene and R-443A as Unacceptable for New
Residential and Light Commercial AC and Heat Pumps, Cold Storage
Warehouses, and Centrifugal and Positive Displacement Chillers
    EPA is proposing to list the refrigerants propylene (R-1270) and R-
443A as unacceptable in new equipment in residential and light
commercial AC and heat pumps, cold storage warehouses, and centrifugal
and positive displacement chillers for commercial comfort AC.
i. What are the affected end-uses?
    The refrigeration and AC end-uses addressed in this action include:
    [cir] Centrifugal and positive displacement chillers;
    [cir] residential and light commercial AC and heat pumps, including
both self-contained units (e.g., window air conditioners, PTACs and
PTHPs, portable AC units) and split systems; and
    [cir] cold storage warehouses.
    EPA has received a submission for R-443A in new residential and
light commercial AC and heat pumps and for new window air conditioners,
a subset of that end-use. We have also received a submission for
propylene for use in new chillers for commercial comfort AC
(centrifugal and positive displacement chillers) and for cold storage
warehouses. Because the two refrigerants, R-443A and propylene, have
similar properties and risk profiles, we reviewed both refrigerants for
all four end-uses.
ii. Which refrigerants is EPA proposing to list as unacceptable?
    Propylene, also known as propene or R-1270, is a HC with three
carbons, the chemical formula C3H6, and the CAS
Reg. No. 115-17-1. R-443A is a HC blend \74\ consisting of 55 percent

propylene, 40 percent propane, and five percent isobutane by weight.
---------------------------------------------------------------------------

    \74\ EPA notes that under the SNAP program, we review and list
refrigerants with specific compositions (59 FR 13,044; March 18,
1994). To the extent possible, we follow ASHRAE's designations for
refrigerants. Blends of refrigerants must be reviewed separately.
For example, we consider each blend of propane with isobutane to be
a different and unique refrigerant, and each would require separate
submission, review and listing.
---------------------------------------------------------------------------

iii. How do these proposed unacceptable refrigerants compare to other
refrigerants for these end-uses with respect to SNAP criteria?
    The SNAP program considers a number of environmental criteria when
evaluating substitutes: ODP; climate effects, primarily based on GWP;
local air quality impacts, particularly potential impacts on smog
formation from emissions of VOC; ecosystem effects, particularly from
negative impacts on aquatic life. These and other environmental and
health risks (e.g., flammability, exposure, and toxicity) are discussed
below. In addition, a technical support document \75\ that provides the
Federal Register citations concerning data on the SNAP criteria (e.g.,
ODP, GWP, VOC, toxicity, flammability) for acceptable alternatives in
the relevant end-uses may be found in the docket for this rulemaking
(EPA-HQ-OAR-2015-0663).
---------------------------------------------------------------------------

    \75\ EPA, 2016b. Draft Tables of Alternatives for End-Uses
Considered in the Notice of Proposed Rule Making, Protection of
Stratospheric Ozone: Listing Modifications for Certain Substitutes
under the Significant New Alternatives Policy Program. March, 2016.
---------------------------------------------------------------------------

(a) Environmental Impacts
    Propylene and R-443A have an ODP of zero. Many acceptable
substitutes in the refrigeration and AC end-uses addressed in this
proposed rule also have an ODP of zero (e.g., HFCs, HFOs,
CO2, ammonia, HCs, and not-in-kind technologies).\76\ Of the
acceptable refrigerants having an ODP, they have ODPs ranging from
0.00024 to 0.047.77 78 Thus, propylene and R-443A have ODPs
comparable to or less than the ODPs of other alternatives in the end-
uses proposed in this rule.
---------------------------------------------------------------------------

    \76\ We assume that substitutes containing no chlorine, bromine,
or iodine have an ODP of zero.
    \77\ EPA, 2016b. Draft Tables of Alternatives for End-Uses
Considered in the Notice of Proposed Rule Making, Protection of
Stratospheric Ozone: Listing Modifications for Certain Substitutes
under the Significant New Alternatives Policy Program. March, 2016.
    \78\ Under EPA's phaseout regulations, virgin HCFC-22, HCFC-
142b, and blends containing HCFC-22 or HCFC-142b may only be used to
service existing appliances. Consequently, virgin HCFC-22, HCFC-142b
and blends containing HCFC-22 or HCFC-142b may not be used to
manufacture new pre-charged appliances or appliance components or to
charge new appliances assembled onsite. Substitutes containing these
HCFCs have ODPs ranging from 0.01 to 0.065. Class I and II ODS
historically used as refrigerants in these end-uses have ODPs that
range from 0.01 to 1.0.
---------------------------------------------------------------------------

    Propylene and the components of R-443A have relatively low GWPs of
less than ten. As shown in Table 4, GWPs of acceptable refrigerants in
these end-uses range from zero to 3,990, depending on the specific end-
use. (Elsewhere in this proposal, we propose to find unacceptable a
number of higher GWP blends for use in new chillers and new cold
storage warehouses; if that portion of this proposed rule was finalized
as proposed, the highest GWP for any acceptable refrigerant in new
chillers would be 630 and in new cold storage warehouses would be
approximately 1,830.) The GWPs of propylene and R-443A are comparable
to or higher than those of CO2, propane, isobutane, R-441A,
ammonia, HFO-1234ze(E), trans-1-chloro-3,3,3-trifluoroprop-1-ene, and
not-in-kind technologies such as Stirling cycle, water/lithium bromide
absorption, dessicant cooling, or evaporative cooling, each of which is
acceptable in new equipment for one or more of the four proposed end-
uses. In addition, propylene and R-443A have lower GWPs than those of
ODS historically used in these end-uses, CFC-12 (GWP = 10,900); HCFC-22
(GWP = 1,810); and R-502 (GWP = 4,660).\79\
---------------------------------------------------------------------------

    \79\ 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., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M. Tignor
and H.L. Miller (eds.). Cambridge University Press, Cambridge,
United Kingdom and New York, NY, USA. This document is accessible
at: www.ipcc.ch/publications_and_data/ar4/wg1/en/contents.html.

  Table 4--GWP, ODP, and VOC Status of Propylene and R-443A Compared to Other Refrigerants in New Equipment for
 Residential and Light Commercial AC and Heat Pumps, Cold Storage Warehouses, Centrifugal Chillers and Positive
                                          Displacement Chillers 1 2 3 4
----------------------------------------------------------------------------------------------------------------
           Refrigerants                GWP               ODP                   VOC                Proposal
----------------------------------------------------------------------------------------------------------------
Propylene, R-443A................          2-3  0...................  Yes.................  Unacceptable.
----------------------------------------------------------------------------------------------------------------
                             New Residential and Light Commercial AC and Heat Pumps
----------------------------------------------------------------------------------------------------------------
HFC-32 \3\, HFC-134a, R-404A, R-     675-3,990  0...................  No..................  No change.
 407A, R-407C, R-407F, R-410A, R-
 410B, R-417A, R-421A, R-507A.
R-290 \ 3\, R-441A \3\, THR-03         3-3,390  0...................  Yes \4\.............  No change.
 \3\, R-125/R-134a/R-600a (28.1/
 70.0/1.9), R-125/R-290/R-134a/R-
 600a (55.0/1.0/42.5/1.5), R-
 422B, R-422C, R-422D, R-424A, R-
 434A, R-437A, R-438A, RS-44
 (2003 formulation).
----------------------------------------------------------------------------------------------------------------
                                           New Cold Storage Warehouses
----------------------------------------------------------------------------------------------------------------
CO2, R-450A, R-513A..............        1-630  0-0.040.............  No..................  No change.
IKON A, IKON B, RS-24 (2002           30-1,825  0...................  Yes \4\.............  No change.
 composition), RS-44, SP34E, THR-
 02, THR-03, THR-04.
----------------------------------------------------------------------------------------------------------------
                                            New Centrifugal Chillers
----------------------------------------------------------------------------------------------------------------
Ammonia, HFO-1234ze(E), trans-1-         0-630  0-0.00034...........  No..................  No change.
 chloro-3,3,3-trifluoroprop-1-
 ene, R-450A, R-513A.
IKON A, IKON B, THR-02...........       30-920  Not public..........  Yes \4\.............  No change.
----------------------------------------------------------------------------------------------------------------
                                       New Positive Displacement Chillers
----------------------------------------------------------------------------------------------------------------
Ammonia, HFO-1234ze(E), R-450A, R-       0-631  0...................  No..................  No change.
 513A.

IKON B, THR-02...................        0-920  0...................  Yes \4\.............  No change.
----------------------------------------------------------------------------------------------------------------
\1\ The table does not include not-in-kind technologies listed as acceptable for the stated end-use.
\2\ HCFC-22 and several blends containing HCFCs are also listed as acceptable but their use is severely
  restricted by the phasedown in HCFC production and consumption.
\3\ Listed only for use in room AC units.
\4\ One or more constituents of the refrigerant are VOC.

    In addition to global impacts on the atmosphere, EPA evaluated
potential impacts of propylene and the components of R-443A on local
air quality. Propylene and the three components of R-443A, propylene,
propane and isobutane are not excluded from the definition of VOC under
CAA regulations (see 40 CFR 51.100(s)) addressing the development of
SIPs to attain and maintain the NAAQS. However, there is a significant
difference in the photochemical reactivity between propylene and the
other two HCs. Propylene, because it has an unsaturated double bond
between two carbons, is significantly more reactive in the atmosphere
than propane, the saturated HC with the same number of carbon atoms,
and isobutane. For example, the Maximum Incremental Reactivity (MIR) of
propylene, in gram ozone per gram of the substance, is 11.57 while the
MIR of propane is 0.56 g O3/g and the MIR of isobutane is
1.34 g O3/g.\80\ Thus, propylene is roughly 21 times more
reactive than propane and roughly nine times more reactive than
isobutane for the same mass. Propylene is also more than 100 times more
reactive than HFC-134a (MIR < 0.1) and a number of other HFCs
acceptable for these end-uses and is significantly more reactive than
unsaturated halogenated substitutes in these end-uses, such as HFO-
1234yf (MIR = 0.28), HFO-1234ze(E) (MIR = 0.098), or trans-1-chloro-
3,3,3-trifluoroprop-1-ene (Solstice \TM\ 1233zd(E)) (MIR = 0.040).
---------------------------------------------------------------------------

    \80\ ICF, 2014a. Assessment of the Potential Impact of
Hydrocarbon Refrigerants on Ground Level Ozone Concentrations.
February, 2014.
---------------------------------------------------------------------------

    Based on analyses described below, EPA estimates that potential
emissions of saturated HCs if used as refrigerant substitutes in all
end-uses in the refrigeration and AC sector would have little impact on
local air quality, while emissions of propylene, including propylene
from R-443A, could have a significant negative impact.\81\
---------------------------------------------------------------------------

    \81\ Ibid.
---------------------------------------------------------------------------

    EPA analyzed a number of scenarios to consider the potential
impacts on local air quality if HC refrigerants were used widely. We
used EPA's Vintaging Model to estimate the HC emissions from these
scenarios and EPA's Community Multiscale Air Quality (CMAQ) model to
assess their potential incremental contributions to ground-level ozone
concentrations.\82\ The first analysis assumed that all refrigerant
used was emitted to the atmosphere, as it could be if refrigerants were
exempted from the venting prohibition of CAA section 608. In that
highly conservative scenario, the model predicted that the maximum
increase in the 8-hour average ground-level ozone concentration would
be 0.72 parts per billion (ppb) in Los Angeles if the most reactive
saturated HC, isobutane, were the only refrigerant and it was all
emitted to the atmosphere. If the unsaturated HC propylene was assumed
to be the only refrigerant used in equipment and it was all emitted (if
it were to be exempted from the venting prohibition under CAA section
608), the model predicted that the maximum increase in the 8-hour
average ground-level ozone concentration would be 6.61 ppb in Los
Angeles, which is the area with the highest level of ozone pollution in
the United States. For purposes of comparison, the ground-level ozone
limit under the NAAQS has been 75 ppb since 2008.\83\ We have concerns
that widespread emissions of propylene from use as a refrigerant could
interfere with the ability of some nonattainment areas to reach
attainment, both with the 2008 NAAQS and the new, more stringent
standard.
---------------------------------------------------------------------------

    \82\ ICF, 2014a. Assessment of the Potential Impact of
Hydrocarbon Refrigerants on Ground Level Ozone Concentrations.
February, 2014.
    \83\ The standard has recently been lowered to 70 ppb (80 FR
65292; October 26, 2015).
---------------------------------------------------------------------------

    EPA also performed less conservative analyses that considered the
end-uses where these refrigerants would more likely be used, based upon
submissions received and upon end-uses where there are industry
standards addressing the use of flammable refrigerants. Propylene was
previously listed as an acceptable substitute in industrial process
refrigeration. EPA has received submissions for use of R-443A in
residential and light commercial AC and heat pumps and window air
conditioners. We have received a SNAP submission for use of propylene
in cold storage warehouses and in commercial comfort AC in chillers,
and have received inquiries about using propylene in retail food
refrigeration. In addition, EPA is aware that UL has developed
standards addressing use of flammable refrigerants in stand-alone
retail food refrigeration equipment and coolers; vending machines;
water coolers; commercial ice machines; household refrigerators and
freezers; and room air conditioners; and is currently developing
revisions to UL 1995 for residential AC equipment. Thus, we considered
scenarios where propylene would be used and emitted (1) in all
stationary AC and refrigeration end-uses, but excluding MVAC, (2) in
all refrigeration end-uses and all AC end-uses except for MVAC and
chillers for commercial comfort AC. For further details on the
scenarios and end-uses in the analysis, see the docket for this
rulemaking.\84\
---------------------------------------------------------------------------

    \84\ ICF, 2016g. Significant New Alternatives Policy Program.
Refrigeration and Air Conditioning Sector Risk Screen on Substitutes
in Chillers and Cold Storage Warehouses. Substitute: Propylene (R-
1270).
---------------------------------------------------------------------------

    Based on this still conservative assessment of refrigerant use, we
found that if all the refrigerant in appliances in the end-uses
analyzed were to be emitted, there would be a worst-case impact of 4.47
ppb ozone in the Los Angeles area. In the other cities examined in the
analysis, Houston and Atlanta, which have also had historically high
levels of ambient ozone, impacts were smaller (as much as 0.67 and 0.39
ppb, respectively).\85\ Approximately 72-73 percent of the emissions
were estimated to come from the residential and light commercial AC and
heat pumps end-use in those less conservative analyses, indicating that
emissions from this end-use could have a particularly large impact.
Both the

most conservative as well as the less conservative but more probable
assessments indicated there could be significant air quality impacts of
these refrigerants if they are released to the atmosphere.
---------------------------------------------------------------------------

    \85\ Ibid.
---------------------------------------------------------------------------

    A more recent analysis specifically examining use of R-443A and
propylene in residential and light commercial AC and heat pumps, cold
storage warehouses, and commercial comfort AC (centrifugal and positive
displacement chillers) found noticeable impacts from these end-uses. If
propylene were the only refrigerant in these end-uses and it was
emitted from residential and light commercial AC and heat pumps and
cold storage warehouses,\86\ the analysis indicated there would be a
worst-case impact of 4.45 ppb ozone in the Los Angeles area, 1.21 ppb
in Houston, and 0.65 in Atlanta, respectively.87 88 Assuming
that propylene were used in all cold storage warehouses and centrifugal
and positive displacement chillers; room air conditioners could use
either R-443A or the currently listed VOC refrigerants propane or R-
441A; other residential and light commercial AC and heat pumps all used
R-443A; and these refrigerants were all emitted from cold storage
warehouses and residential and light commercial AC and heat pumps,
there would be a worst-case impact of 2.57 ppm ozone in the Los Angeles
area, 0.77 ppb in Houston, and 0.44 ppb in Atlanta,
respectively.89 90
---------------------------------------------------------------------------

    \86\ The analysis assumed that local and state safety
regulations required recovery of refrigerant from commercial comfort
air conditioning equipment.
    \87\ ICF, 2016f. Significant New Alternatives Policy Program.
Refrigeration and Air Conditioning Sector Risk Screen on Substitutes
in Residential and Light Commercial Air Conditioning and Heat Pumps.
Substitute: R-443A.
    \88\ ICF, 2016g. Significant New Alternatives Policy Program.
Refrigeration and Air Conditioning Sector Risk Screen on Substitutes
in Chillers and Cold Storage Warehouses. Substitute: Propylene (R-
1270).
    \89\ ICF, 2016f. Significant New Alternatives Policy Program.
Refrigeration and Air Conditioning Sector Risk Screen on Substitutes
in Residential and Light Commercial Air Conditioning and Heat Pumps.
Substitute: R-443A.
    \90\ ICF, 2016g. Significant New Alternatives Policy Program.
Refrigeration and Air Conditioning Sector Risk Screen on Substitutes
in Chillers and Cold Storage Warehouses. Substitute: Propylene (R-
1270).
---------------------------------------------------------------------------

    Propylene and R-443A in the proposed end-uses would be subject to
the CAA section 608 venting prohibition unless EPA were to issue a
final rule specifically exempting them; EPA is not proposing such an
exemption in this rulemaking. While potential air quality impacts of
propylene and R-443A would likely be reduced through the CAA section
608 venting prohibition, we do not consider this sufficient to mitigate
the risks of these refrigerants in the proposed end-uses, particularly
in light of their photochemical reactivity and toxicity. EPA is not
aware of commercially available recovery equipment for flammable
refrigerants (e.g., built with spark-proof components and other
features to reduce flammability risks), and without such equipment,
emissions could occur. Further, other emissions could occur that are
not subject to the venting prohibition and no equipment is free of
refrigerant emissions. Because of the reactivity of these refrigerants,
those emissions could interfere with the ability of some nonattainment
areas to reach attainment, both with the 2008 NAAQS and the new, more
stringent standard.
    Ecosystem effects, primarily effects on aquatic life, of the
substitutes are expected to be small as are the effects of other
acceptable substitutes. Propylene, propane and isobutane are all highly
volatile and would evaporate or partition to air, rather than
contaminate surface waters. Neither propylene nor R-443A pose a greater
risk of aquatic or ecosystem effects than those of other substitutes
for these uses.
(b) Flammability
    Propylene and R-443A are both designated as A3 refrigerants
according to ASHRAE 34-2013 and subsequent addenda. Thus, their
flammability is comparable to that of ethane, propane, isobutane, and
R-441A, other refrigerants that EPA has listed as acceptable, subject
to use conditions, in a number of end-uses (76 FR 78832, December 20,
2011; 80 FR 19454, April 10, 2015).
    Due to their flammable nature, propylene and R-443A could pose a
significant safety concern for workers and consumers if they are not
properly handled. In the presence of an ignition source (e.g., static
electricity spark resulting from closing a door, using a torch during
service, or a short circuit in wiring that controls the motor of a
compressor), an explosion or a fire could occur when the concentration
of refrigerant exceeds its LFL. The LFLs of the substitutes are: 2.03
percent for R-443A \91\ and 2.0 percent for propylene.\92\
---------------------------------------------------------------------------

    \91\ A.S. Trust & Holdings, 2014. Response to Incompleteness
Letter from A.S. Trust & Holdings to EPA--Sent March 7, 2014.
    \92\ Airgas, 2015. Safety Data Sheet for Propylene.
---------------------------------------------------------------------------

    To determine whether flammability would be a concern for
manufacturing and service personnel or for consumers, EPA analyzed a
plausible worst-case scenario to model a catastrophic release of the
refrigerants. The worst-case scenario analysis for each refrigerant
revealed that even if the full charge of a window AC unit is emitted
within one minute, neither of these refrigerants reached their
respective LFLs. However, for larger residential AC systems, such as
for a unitary split AC system, charges are significantly higher, and a
catastrophic leak of refrigerant inside a building could result in
surpassing the LFL.93 94 For chillers, our risk screen found
that an instantaneous release of the entire charge of propylene from a
small chiller (charge size of around 12 kg) would not exceed the LFL,
but release of larger charge sizes (e.g., 315 kg) would result in
exceeding the LFL by ten-fold or more.\95\ Thus, flammability would be
a concern for equipment with large charge sizes.
---------------------------------------------------------------------------

    \93\ ICF, 2016f. Significant New Alternatives Policy Program.
Refrigeration and Air Conditioning Sector Risk Screen on Substitutes
in Residential and Light Commercial Air Conditioning and Heat Pumps.
Substitute: R-443A.
    \94\ ICF, 2016g. Significant New Alternatives Policy Program.
Refrigeration and Air Conditioning Sector Risk Screen on Substitutes
in Chillers and Cold Storage Warehouses. Substitute: Propylene (R-
1270).
    \95\ Ibid.
---------------------------------------------------------------------------

    EPA also reviewed the submitters' detailed assessments of the
probability of events that might create a fire and engineering risk and
approaches to avoid sparking from the refrigeration equipment. Further
information on these analyses and EPA's risk assessments are available
in public docket EPA-HQ-OAR-2015-0663. Manufacturing and service
personnel or consumers may not be familiar with refrigeration or AC
equipment containing a flammable refrigerant. Thus, additional risk
mitigation would be appropriate. Use conditions such as those recently
finalized for ethane, isobutane, propane, and R-441A could potentially
be adopted by regulation as use conditions to mitigate flammability
concerns from propylene and R-443A in end-uses for self-contained
refrigeration and AC equipment such as stand-alone retail food
refrigeration units, household refrigerators and freezers, vending
machines, and room air conditioners for residential and light
commercial AC and heat pumps. We further note that refrigerant handling
equipment designed to be used safely with flammable refrigerants are
not commercially available in the United States nor are standards to
test and certify such equipment in place. Assuming these substitutes
would not be exempted from the venting prohibition under CAA section
608 due to potential local air quality impacts, the lack of such
equipment and standards for refrigerant recovery calls into

question whether flammability risks could be adequately addressed
through use conditions at this time.
(c) Toxicity
    In evaluating potential toxicity impacts of propylene and R-443A on
human health, EPA considered both occupational risk, and for end-uses
in the household or in retail establishments, also consumer risks. EPA
investigated the risk of asphyxiation and of exposure to toxic levels
of refrigerant for a plausible worst-case scenario and a typical use
scenario for each refrigerant. In the worst-case scenario of a
catastrophic leak, we modeled release of the unit's full charge within
one minute into a confined space to estimate concentrations that might
result. We considered a conservatively small space appropriate to each
end-use, such as a small utility room of 18 m\3\ for a unitary split AC
system, or a small bedroom of 41 m\3\ for a room air conditioner. EPA
used the same assumptions when evaluating other substitutes, such as
CO2, HFC-32, propane and R-441A.
    To evaluate toxicity of both refrigerants, EPA estimated the
maximum TWA exposure both for a short-term exposure scenario, with a
30-minute TWA exposure, and for an 8-hour TWA that would be more
typical of occupational exposure for a technician servicing the
equipment. We compared these short-term and long-term exposure values
to relevant industry and government workplace exposure limits for
propylene and the components of R-443A (including potential
impurities). The modeling results indicate that both the short-term
(30-minute) and long-term (8-hour) worker exposure concentrations would
be below the relevant workplace exposure limits, such as the OSHA PEL,
the NIOSH REL, or the ACGIH's TLV in cold storage warehouses,
commercial comfort AC equipment, and residential and light commercial
AC and heat pumps.\96\ Because there is not an established short-term
exposure limit (STEL) for propylene, propane, or isobutane, we
considered information on short-term exposure such as a short-term
excursion limit based on the TLV or the National Research Council's
AEGL. The respective workplace exposure limits we considered for the
various compounds, including components of the refrigerant blend R-
443A, are as follows:
---------------------------------------------------------------------------

    \96\ Ibid.
---------------------------------------------------------------------------

     Isobutane: 800 ppm REL on 10-hr TWA; 6,900 ppm over 30
minutes
     Propane: 1,000 ppm PEL/TLV on 8-hr TWA; 6,900 ppm AEGL-1
over 30 minutes
     Propylene: 500 ppm TLV on 8-hr TWA; 1,500 ppm excursion
limit over 30 minutes
    In comparison, HFCs and the HFC components of acceptable
substitutes in these end-uses, have exposure limits, such as WEELs from
the AIHA or manufacturer acceptable exposure limits, of 1,000 ppm on an
8-hr TWA and the HC components of both the acceptable refrigerants and
those proposed unacceptable have exposure limits ranging from 500 to
1,000 ppm (8-hr TWA for TLVs from ACGIH and 10-hr TWA for recommended
exposure limits (RELs) from NIOSH). HFOs acceptable in centrifugal and
positive displacement chillers have WEELs of 800 ppm. Both the
acceptable refrigerants and the proposed unacceptable refrigerants are
able to be used in these end-uses in accordance with their respective
workplace exposure limits.
    For equipment with which consumers might come into contact, such as
residential air conditioners and heat pumps, EPA also performed a
consumer exposure analysis. In this analysis, we examined potential
catastrophic release of the entire charge of the substitute in one
minute under a worst-case scenario. We did not examine exposure to
consumers in cold storage warehouses and commercial comfort AC
(chillers), since such equipment is typically used in workplaces where
access is controlled and not in homes or public spaces. The analysis
was undertaken to determine the 30-minute TWA exposure levels for the
substitute, which were then compared to the toxicity limits to assess
the risk to consumers.
    EPA considered toxicity limits for consumer exposure that reflect a
short-term exposure such as might occur at home or in a store or other
public setting where a member of the general public could be exposed
and could then escape. Specific toxicity limits that we used in our
analysis of consumer exposure include:

 Isobutane: 6,900 ppm over 30 minutes \97\
---------------------------------------------------------------------------

    \97\ EPA selected this value as analogous to the AEGL-1 of 6,900
ppm over 30 minutes for propane, another saturated hydrocarbon with
similar chemical properties.
---------------------------------------------------------------------------

 Propane: 6,900 ppm AEGL-1 over 30 minutes \98\
---------------------------------------------------------------------------

    \98\ The Acute Emergency Guideline Limit (AEGL) is an emergency
guideline for exposures to the general population (including
susceptible populations) and is not time-weighted. It also considers
the chemical's flammability in addition to its toxicity. EPA
develops a set of AEGL values for a substance for five exposure
periods (10 and 30 minutes, 1 hour, 4 hours and 8 hours). For each
exposure period, three different AEGL values are developed to
address different levels of toxicological impacts. Of relevance for
the modeled scenario is the AEGL-1, which is defined as: ``the
airborne concentration, expressed as parts per million or milligrams
per cubic meter (ppm or mg/m\3\) of a substance above which it is
predicted that the general population, including susceptible
individuals, could experience notable discomfort, irritation, or
certain asymptomatic nonsensory effects. However, the effects are
not disabling and are transient and reversible upon cessation of
exposure.'' While permanent toxicological effects are not expected
up to the AEGL-2 value, this limit is not relevant for this analysis
because at that level, flammability would be a greater concern.
---------------------------------------------------------------------------

 Propylene: 1,500 ppm excursion limit \99\ over 30 minutes
---------------------------------------------------------------------------

    \99\ There are no short term exposure limits available for
propylene (e.g., AEGL-1, NIOSH STEL, ACGIH STEL). This compound is
sufficiently different chemically from propane (e.g., contains a
double bond) that we could not select an analogous AEGL. Therefore,
EPA developed a short-term excursion limit based upon ACGIH
recommendations. The ACGIH recommends that short-term exposures of
chemicals not surpass three times the 8-hr TWA TLV over 15 minutes
and at no time surpass five times the 8-hr TWA TLV. For propylene,
this equates to 1,500 to 2,500 ppm.
---------------------------------------------------------------------------

    The analysis of consumer exposure assumed that 100 percent of the
unit's charge would be released over one minute, at which time the
concentration of refrigerant would peak in an enclosed space, and then
steadily decline. Refrigerant concentrations were modeled under two air
change scenarios, believed to represent the baseline of potential flow
rates for a home or other public space, assuming flow rates of 0.11 and
0.67 ACH.\100\ Under the conservative assumptions used in the consumer
exposure modeling, the estimated 30-minute consumer exposures to the
refrigerants exceed the toxicity limits for the propylene component of
R-443A in all cases but the least conservative. The least conservative
scenario assumed the highest ventilation rate and the lowest charge
size (160 g) evaluated, as well as assuming complete mixing of the
refrigerant rather than stratification (i.e., refrigerant pooling near
the floor). All of the other estimates of exposure exceeded the 1,500
ppm excursion limit for propylene, with estimates ranging from
approximately 1,520 ppm to 9,700 ppm. This occurred for lower or higher
charge sizes ranging from 160 g to 1,500 g; lower or higher ventilation
levels of 0.11 or 0.67 ACH; and, except for the smallest charge size,
whether stratification was assumed to occur or not. In comparison, EPA
previously found that a charge of 180 g of propane

in a room air conditioner could meet its AEGL-1 and a charge of 195 g
of R-441A in a room air conditioner could meet the various short-term
exposure limits for its components under the same assumptions of
ventilation, stratification, and room size.101 102 Thus, EPA
has concern about the exposure levels and toxicity of propylene and R-
443A in residential and light commercial AC and heat pumps.
---------------------------------------------------------------------------

    \100\ ICF, 2016f. Significant New Alternatives Policy Program.
Refrigeration and Air Conditioning Sector Risk Screen on Substitutes
in Residential and Light Commercial Air Conditioning and Heat Pumps.
Substitute: R-443A.
    \101\ ICF, 2014b. Risk Screen on Substitutes for HCFC-22 in
Residential and Light Commercial Air Conditioning and Heat Pumps;
Substitute: Propane (R-290).
    \102\ ICF, 2014c. Risk Screen on Substitutes for HCFC-22 in
Residential and Light Commercial Air Conditioning and Heat Pumps;
Substitute: R-441A.
---------------------------------------------------------------------------

    In comparison, the currently acceptable refrigerants typically have
high acute exposure limits for their components based upon cardiotoxic
effects of halocarbons over 10,000 ppm (e.g., 350,000 cardiotoxic no-
observed adverse effect level for HFC-32 over 5 minutes) or have
components with STELs or AEGLs (e.g., 8,000 ppm 10-minute AEGL-1 for
HFC-134a component). Acute exposure limits for propylene and R-443A's
components range from 1,500 ppm for propylene to 6,900 ppm (AEGL-1 over
30 minutes for propane). Because of the relatively low acute exposure
limit for propylene, acute exposure is a greater concern than for other
acceptable refrigerants in residential and light commercial AC systems
and heat pumps.
    In summary, EPA's concerns about propylene and R-443A encompass
both toxicity and exposure and impacts of these refrigerants on local
air quality.\103\ Other acceptable refrigerants are available in the
same end-uses that offer lower toxicity and air quality impacts, and
similar flammability, GWP, and ODP when compared to R-443A and
propylene. Thus, we are proposing to list propylene and R-443A as
unacceptable in these end-uses because they pose significantly more
risk than other available refrigerants. For further information,
including EPA's risk screens and risk assessments as well as
information from the submitters of the substitutes, see docket EPA-HQ-
OAR-2015-0663.
iv. When would the listings apply?
    EPA proposes that this listing would apply 30 days after the date
of publication of a final rule. To our knowledge, manufacturers and
service technicians are not currently using these substitutes in the
proposed end-uses. We note that EPA has only recently found submissions
complete for these substitutes, and under the SNAP program regulations,
a substitute may not be introduced into interstate commerce prior to 90
days after EPA receives a complete submission. Further, a date of 30
days after the date of publication of a final rule, the same as the
proposed effective date of this regulation, would protect against the
risks of these substitutes at the earliest opportunity.
v. What is the relationship between this proposed SNAP rule and other
federal rules?
    DOE has indicated its intent to issue a proposed energy
conservation standard for portable air conditioners, a subset of the
residential and light commercial air conditioning and heat pumps end-
use. For information on DOE's 2015 Fall Regulatory Agenda, see http://www.reginfo.gov/public/do/eAgendaViewRule?pubId=201510&RIN=1904-AD02.
Information on other federal rules that may apply to centrifugal
chillers, positive displacement chillers, and cold storage warehouses
is available in sections VI.A.4.a.vi, VI.A.4.b.vi, and VI.A.4.c.v
below. We note that since these two refrigerants are currently not
being used in these types of equipment in the United States, we expect
this regulation, if finalized as proposed, would have no impact on
compliance with federal energy conservation standards.
vi. On which topics is EPA specifically requesting comment?
    EPA requests comment on all aspects of this proposal. In
particular, we request comment on our proposal to list the refrigerants
propylene (R-1270) and R-443A as unacceptable in new equipment in
residential and light commercial AC and heat pumps, cold storage
warehouses, and centrifugal and positive displacement chillers for
commercial comfort AC. EPA specifically requests comment on the
proposed decision to list these refrigerants as unacceptable 30 days
after the date of publication of a final rule, and the end-uses
proposed here.
4. Proposed Changes in Listing Status
a. Proposed Change of Status for Certain HFC Refrigerants for New
Centrifugal Chillers
    As provided in the following table, EPA is proposing to change the
status of numerous refrigerants from acceptable to unacceptable for new
centrifugal chillers:

    Table 5--Proposed Change of Status Decisions for New Centrifugal
                                Chillers
------------------------------------------------------------------------
           End-use                 Substitutes        Proposed decision
------------------------------------------------------------------------
Centrifugal chillers (new     FOR12A, FOR12B, HFC-  Unacceptable as of
 only).                        134a, HFC-227ea,      January 1, 2024,
                               HFC-236fa, HFC-       except where
                               245fa, R-125/134a/    allowed under a
                               600a (28.1/70/1.9),   narrowed use limit.
                               R-125/290/134a/600a
                               (55.0/1.0/42.5/
                               1.5), R-404A, R-
                               407C, R-410A, R-
                               410B, R-417A, R-
                               421A, R-422B, R-
                               422C, R-422D, R-
                               423A, R-424A, R-
                               434A, R-438A, R-
                               507A, RS-44 (2003
                               composition), and
                               THR-03.
Centrifugal Chillers (new     HFC-134a............  Acceptable, subject
 only).                                              to narrowed use
                                                     limits, for
                                                     military marine
                                                     vessels, as of
                                                     January 1, 2024.
Centrifugal Chillers (new     HFC-134a and R-404A.  Acceptable, subject
 only).                                              to narrowed use
                                                     limits, for human-
                                                     rated spacecraft
                                                     and related support
                                                     equipment, as of
                                                     January 1, 2024.
------------------------------------------------------------------------

i. What is the affected end-use?
(a) Overview of Equipment Covered
    In the initial rule establishing the SNAP program (59 FR 13044;
March 18, 1994), EPA included within the refrigeration and AC sector
the end-use ``commercial comfort air conditioning'' and then elaborated
on that end-use saying that ``CFCs are used in several different types
of mechanical commercial comfort AC systems, known as chillers.'' EPA
indicated ``that over time, existing cooling capacity [from chillers]
will be either retrofitted or replaced by systems using non-CFC
refrigerants in a vapor compression cycle or by alternative
technologies.''

We also explained in that rule that vapor compression chillers can be
categorized by the types of compressor used, including centrifugal,
rotary, screw, scroll and reciprocating compressors. These compressor
types are also divided into centrifugal and positive displacement
chillers, the latter of which includes those with reciprocating, screw,
scroll or rotary compressors. This section of the proposed rule covers
centrifugal chillers.
    Centrifugal chillers are equipment that utilize a centrifugal
compressor in a vapor-compression refrigeration cycle. Centrifugal
chillers are typically used for commercial comfort AC although other
uses do exist. Centrifugal chillers can be found in office buildings,
hotels, arenas, convention halls, airport terminals and other
buildings. Centrifugal chillers tend to be used in larger buildings.
    For commercial comfort and some other applications, centrifugal
chillers typically cool water that is then pumped to fan coil units or
other air handlers to cool the air that is supplied to the occupied
spaces transferring the heat to the water. The heat absorbed by the
water can then be used for heating purposes, and/or can be transferred
directly to the air (``air-cooled''), to a cooling tower or body of
water (``water-cooled'') or through evaporative coolers (``evaporative-
cooled''). A centrifugal chiller or a group of centrifugal chillers
could similarly be used for district cooling where the chiller plant
cools water or another fluid that is then pumped to multiple locations
being served such as several different buildings within the same
complex. All such centrifugal chillers are covered by this section of
the proposed rule.
    Centrifugal chillers are used for other applications besides
commercial comfort AC and are covered under this section of the
proposed rule. For instance, centrifugal chillers used to cool
equipment, such as in data centers, are covered under this section of
the proposed rule.
(b) What other types of equipment are used for similar applications but
are not covered by this section of the proposed rule?
    Other equipment including packaged rooftop units and split system
air conditioners, both of which fall under the SNAP end-use ``household
and light commercial air conditioning,'' can also be used for
commercial comfort AC, typically for smaller capacity needs. These
equipment types are not centrifugal chillers and hence are not covered
under this section of the proposed rule.
(c) What refrigerants are used in centrifugal chillers?
    Centrifugal chillers historically employed either CFC-11 (called
``low pressure chillers'') or CFC-12 (``high pressure chillers''),
although other CFCs have been used, including CFC-114 and R-500 (a
blend of CFC-12 and HFC-152a). When the production and consumption of
CFCs were phased out in the United States in the 1990s, centrifugal
chillers was one of the first end-uses to be redesigned for alternative
refrigerants and HCFC-123 and HFC-134a became the primary refrigerants
used in centrifugal chillers. HCFC-123 was used in low pressure
chillers while HFC-134a was used in high pressure chillers. Both of
these alternatives continue to be used today. HCFC-22 was also used in
some centrifugal chillers, primarily only in equipment produced before
approximately the year 2000. HFC-245fa was also identified as a
possible refrigerant for low pressure centrifugal chillers, but has
found only limited use.
    More recently, centrifugal chillers that use alternatives listed as
acceptable have been demonstrated or announced. For instance, one
manufacturer has introduced centrifugal chillers using trans-1-chloro-
3,3,3-trifluoroprop-1-ene, a nonflammable low-GWP refrigerant.\104\
---------------------------------------------------------------------------

    \104\ Cooling Post, 2014. Trane first with 1233zd chiller, June
30, 2014. This document is accessible at www.coolingpost.com/world-news/trane-first-with-1233zd-chiller/.
---------------------------------------------------------------------------

ii. Which refrigerants is EPA proposing to list as unacceptable?
    For new centrifugal chillers, EPA is proposing to change the status
of the following refrigerants from acceptable to unacceptable: FOR12A,
FOR12B, HFC-134a, HFC-227ea, HFC-236fa, HFC-245fa, R-125/134a/600a
(28.1/70/1.9), R-125/290/134a/600a (55.0/1.0/42.5/1.5), R-404A, R-407C,
R-410A, R-410B, R-417A, R-421A, R-422B, R-422C, R-422D, R-423A, R-424A,
R-434A, R-438A, R-507A, RS-44 (2003 composition), and THR-03.
iii. How do these proposed unacceptable refrigerants compare to other
refrigerants for this end-use with respect to SNAP criteria?
    For new centrifugal chillers, acceptable refrigerants for which we
are not proposing a change of status in this end-use include: HFO-
1234ze(E), IKON A, IKON B, R-450A, R-513A, R-717 (ammonia), THR-02, and
trans-1-chloro-3,3,3-trifluoroprop-1-ene.
    The SNAP program considers a number of environmental criteria when
evaluating substitutes: ODP; climate effects, primarily based on GWP;
local air quality impacts, particularly potential impacts on smog
formation from emissions of VOC; and ecosystem effects, particularly
from negative impacts on aquatic life. These and other environmental
and health risks are discussed below. In addition, a technical support
document \105\ that provides the Federal Register citations concerning
data on the SNAP criteria (e.g., ODP, GWP, VOC, toxicity, flammability)
for acceptable alternatives for new centrifugal chillers may be found
in the docket for this rulemaking (EPA-HQ-OAR-2015-0663).
---------------------------------------------------------------------------

    \105\ EPA, 2016b. Draft Tables of Alternatives for End-Uses
Considered in the Notice of Proposed Rule Making, Protection of
Stratospheric Ozone: Listing Modifications for Certain Substitutes
under the Significant New Alternatives Policy Program. March, 2016.
---------------------------------------------------------------------------

(a) Environmental Impacts
    The refrigerants for which we are proposing a change of status have
an ODP of zero. Other alternatives also with an ODP of zero that we are
not proposing a change of status for new centrifugal chillers include
HFO-1234ze(E), IKON A, IKON B, R-450A, R-513A, R-717, and THR-02. Also,
the alternative refrigerant trans-1-chloro-3,3,3-trifluoroprop-1-ene
has an ODP of 0.00024 to 0.00034.106 107 Estimates of this
compound's potential to deplete the ozone layer indicate that even with
worst-case estimates of emissions, which assume that this compound
would substitute for all compounds it could replace, the impact on
global atmospheric ozone abundance would be statistically
insignificant.\108\ Thus, the acceptable alternatives not subject to
the proposed status change have ODPs lower than or of the same
practical effect to the ODPs of other alternatives for which EPA is
proposing a change of status, and lower than the ODPs of ODS
historically used in this end-use. The refrigerants we are proposing to
find unacceptable through this action have GWPs ranging from about 920
to 9,810. As shown in Table 6, other alternatives

acceptable for this end-use have GWPs ranging from zero to 630.
---------------------------------------------------------------------------

    \106\ Wang D., Olsen S., Wuebbles D. 2011. ``Preliminary Report:
Analyses of tCFP's Potential Impact on Atmospheric Ozone.''
Department of Atmospheric Sciences. University of Illinois, Urbana,
IL. September 26, 2011.
    \107\ Patten and Wuebbles, 2010. ``Atmospheric Lifetimes and
Ozone Depletion Potentials of trans-1-chloro-3,3,3-
trichloropropylene and trans-1,2-dichloroethylene in a three-
dimensional model.'' Atmos. Chem. Phys., 10, 10867-10874, 2010.
    \108\ Wang D., Olsen S., Wuebbles D. 2011. ``Preliminary Report:
Analyses of tCFP's Potential Impact on Atmospheric Ozone.''
Department of Atmospheric Sciences. University of Illinois, Urbana,
IL. September 26, 2011.

               Table 6--GWP, ODP, and VOC Status of Refrigerants in New Centrifugal Chillers 1 2 3
----------------------------------------------------------------------------------------------------------------
           Refrigerants                  GWP             ODP               VOC                  Proposal
----------------------------------------------------------------------------------------------------------------
Ammonia, HCFC-123, HCFC-124, HFO-           0-630         0-0.022  No.................  No change.
 1234ze(E), R-450A, R-513A, trans-
 1-chloro-3,3,3-trifluoroprop-1-
 ene.
IKON A, IKON B, THR-02...........          30-560               0  Yes \3\............  No change.
HFC-134a, HFC-245fa..............     1,030-1,430               0  No.................  Unacceptable.
FOR12A, FOR12B, THR-03...........       920-1,220               0  Yes \3\............  Unacceptable.
R-407C, R-410A, R-410B, R-421A, R-   1,770 -3,220               0  No.................  Unacceptable.
 423A, HFC-227ea.
R-125/134a/600a (28.1/70/1.9), R-    1,770 -3,250               0  Yes \3\............  Unacceptable.
 125/290/134a/600a (55/1/42.5/
 1.5), R-417A, R-422B, R-422C, R-
 422D, R-424A, R-434A, R-438A, RS-
 44 (2003 composition).
HFC-236fa, R-404A, R-507A........     3,920-9,810               0  No.................  Unacceptable.
----------------------------------------------------------------------------------------------------------------
\1\ The table does not include not-in-kind technologies listed as acceptable for the stated end-use.
\2\ HCFC-22, HCFC-123, HCFC-124, and several blends containing HCFCs are also listed as acceptable but their use
  is severely restricted by the phasedown in HCFC production and consumption.
\3\ One or more constituents of the refrigerant are VOC.

    One of the refrigerant blends not subject to the proposed status
change (THR-02), as well as several of the substitutes subject to the
proposed status change, include small amounts of R-290 (propane), R-600
(butane) or other substances that are VOCs. These amounts are small and
for this end-use are not expected to contribute significantly to ground