[Federal Register Volume 87, Number 82 (Thursday, April 28, 2022)]
[Proposed Rules]
[Pages 25170-25178]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-08922]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 51
[EPA-HQ-OAR-2021-0420; FRL-8371-02-OAR]
RIN 2060-AV24
Air Quality: Revision to the Regulatory Definition of Volatile
Organic Compounds--Exclusion of (2E)-1,1,1,4,4,4-hexafluorobut-2-ene
(HFO-1336mzz(E))
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.
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SUMMARY: The U.S. Environmental Protection Agency (EPA) is proposing to
revise the EPA's regulatory definition of volatile organic compounds
(VOC) under the Clean Air Act (CAA). This action proposes to add (2E)-
1,1,1,4,4,4-hexafluorobut-2-ene (also known as trans-1,1,1,4,4,4-
hexafluorobut-2-ene, and HFO-1336mzz(E); CAS number 66711-86-2) to the
list of compounds
[[Page 25171]]
excluded from the regulatory definition on the basis that this compound
makes a negligible contribution to tropospheric ozone (O3)
formation.
DATES: Comments must be received on or before June 27, 2022.
ADDRESSES: You may send comments, identified by Docket ID No. EPA-HQ-
OAR-2021-0420, by any of the following methods:
Federal eRulemaking Portal: https://www.regulations.gov/
(our preferred method). Follow the online instructions for submitting
comments.
Mail: U.S. Environmental Protection Agency, EPA Docket
Center, Docket No. EPA-HQ-OAR-2021-0420, Office of Air and Radiation
Docket, Mail Code 28221T, 1200 Pennsylvania Avenue NW, Washington, DC
20460.
Hand Delivery or Courier (by scheduled appointment only):
EPA Docket Center, WJC West Building, Room 3334, 1301 Constitution
Avenue NW, Washington, DC 20004. The Docket Center's hours of
operations are 8:30 a.m.-4:30 p.m., Monday-Friday (except Federal
Holidays).
Instructions: All submissions received must include the Docket ID
No. for this rulemaking. Comments received may be posted without change
to https://www.regulations.gov/, including any personal information
provided. For detailed instructions on sending comments and additional
information on the rulemaking process, see the ``Public Participation''
heading of the SUPPLEMENTARY INFORMATION section of this document. Out
of an abundance of caution for members of the public and our staff, the
EPA Docket Center and Reading Room are open to the public by
appointment only to reduce the risk of transmitting COVID-19. Our
Docket Center staff also continues to provide remote customer service
via email, phone, and webform. Hand deliveries and couriers may be
received by scheduled appointment only. For further information on EPA
Docket Center services and the current status, please visit us online
at https://www.epa.gov/dockets.
FOR FURTHER INFORMATION CONTACT: Dr. Souad Benromdhane, Office of Air
Quality Planning and Standards, Health and Environmental Impacts
Division, Mail Code C539-07, Environmental Protection Agency, Research
Triangle Park, NC 27711; telephone: (919) 541-4359; fax number: (919)
541-5315; email address: [email protected].
SUPPLEMENTARY INFORMATION:
General Information
Written comments: Submit your comments, identified by Docket ID No.
EPA-HQ-OAR-2021-0420, at https://www.regulations.gov (our preferred
method), or the other methods identified in the ADDRESSES section. Once
submitted, comments cannot be edited or removed from the docket. The
EPA may publish any comment received to its public docket. Do not
submit to EPA's docket at https://www.regulations.gov any information
you consider to be Confidential Business Information (CBI) or other
information whose disclosure is restricted by statute. Multimedia
submissions (audio, video, etc.) must be accompanied by a written
comment. The written comment is considered the official comment and
should include discussion of all points you wish to make. The EPA will
generally not consider comments or comment contents located outside of
the primary submission (i.e., on the web, cloud, or other file sharing
system). For additional submission methods, the full EPA public comment
policy, information about CBI or multimedia submissions, and general
guidance on making effective comments, please visit https://www.epa.gov/dockets/commenting-epa-dockets.
Due to public health concerns related to COVID-19, the EPA Docket
Center and Reading Room are open to the public by appointment only. Our
Docket Center staff also continues to provide remote customer service
via email, phone, and webform. Hand deliveries or couriers will be
received by scheduled appointment only. For further information and
updates on EPA Docket Center services, please visit us online at
https://www.epa.gov/dockets.
The EPA continues to monitor information carefully and continuously
from the Centers for Disease Control and Prevention (CDC), local area
health departments, and our Federal partners so that we can respond
rapidly as conditions change regarding COVID-19.
Table of Contents
I. Does this action apply to me?
II. Background
A. The EPA's VOC Exemption Policy
B. Petition To List HFO-1336mzz(E) as an Exempt Compound
III. The EPA's Assessment of the Petition
A. Contribution to Tropospheric Ozone Formation
B. Potential Impacts on Other Environmental Endpoints
1. Contribution to Stratospheric Ozone Depletion
2. Toxicity
3. Contribution to Climate Change
C. Conclusions
IV. Proposed Action
V. Statutory and Executive Order Reviews
A. Executive Order 12866: Regulatory Planning and Review and
Executive Order 13563: Improving Regulation and Regulatory Review
B. Paperwork Reduction Act (PRA)
C. Regulatory Flexibility Act (RFA)
D. Unfunded Mandates Reform Act (UMRA)
E. Executive Order 13132: Federalism
F. Executive Order 13175: Consultation and Coordination With
Indian Tribal Governments
G. Executive Order 13045: Protection of Children From
Environmental Health and Safety Risks
H. Executive Order 13211: Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution or Use
I. National Technology Transfer and Advancement Act (NTTAA)
J. Executive Order 12898: Federal Actions To Address
Environmental Justice in Minority Populations and Low-Income
Populations
K. Judicial Review
VI. References
I. Does this action apply to me?
Entities potentially affected by this proposed rule include, but
are not necessarily limited to, the following: State and local air
pollution control agencies that adopt and implement regulations to
control air emissions of VOC; and industries manufacturing and/or using
HFO-1336mzz(E) for use in foam blowing, refrigeration, as well as
applications in solvents and aerosol propellants, and other minor uses.
Potential entities that may be affected by this action include the
following:
Table 1--Potentially Affected Entities by North American Industrial Classification System (NAICS) Code
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Category NAICS code Description of regulated entities
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Industry........................................ 325120 Industrial Gas Manufacturing.
Industry........................................ 333242 Semiconductor Machinery Manufacturing.
Industry........................................ 325998 All Other Miscellaneous Chemical Product and
Preparation Manufacturing.
Industry........................................ 326140 Polystyrene Foam Product Manufacturing.
Industry........................................ 326150 Urethane and Other Foam Product (except
Polystyrene) Manufacturing.
[[Page 25172]]
Industry........................................ 333415 Air-Conditioning and Warm Air Heating Equipment
and Commercial and Industrial Refrigeration
Equipment Manufacturing.
Industry........................................ 3363 Motor Vehicle Parts Manufacturing.
Industry........................................ 336611 Ship Building and Repairing.
Industry........................................ 336612 Boat Building.
Industry........................................ 339999 All other Miscellaneous Manufacturing.
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This table is not intended to be exhaustive but rather provides a
guide for readers regarding entities that might be affected by this
deregulatory action. This table lists the types of entities that the
EPA is now aware of that could potentially be affected to some extent
by this action. Other types of entities not listed in the table could
also be affected to some extent. To determine whether your entity is
directly or indirectly affected by this action, you should consult your
state or local air pollution control and/or air quality management
agencies.
II. Background
A. The EPA's VOC Exemption Policy
Tropospheric O3, commonly known as smog, is formed when
VOC and nitrogen oxides (NOX) react in the atmosphere in the
presence of sunlight. Because of the harmful health effects of
O3, the EPA and state governments limit the amount of VOC
that can be released into the atmosphere. Volatile organic compounds
form O3 through atmospheric photochemical reactions, and
different VOC have different levels of reactivity. That is, different
VOC do not react to form O3 at the same speed or form
different amounts of O3. Some VOC react more slowly or form
less O3; therefore, changes in their emissions have limited
effects on local or regional O3 pollution episodes. It has
been the EPA's policy since 1971 that certain organic compounds with a
negligible level of reactivity should be excluded from the regulatory
definition of VOC to focus VOC control efforts on compounds that
significantly affect O3 concentrations. The EPA also
believes that exempting such compounds creates an incentive for
industry to use negligibly reactive compounds in place of more highly
reactive compounds that are regulated as VOC. The EPA lists compounds
that it has determined to be negligibly reactive in its regulations as
being excluded from the regulatory definition of VOC (40 CFR
51.100(s)).
The CAA requires the regulation of VOC for various purposes.
Section 302(s) of the CAA specifies that the EPA has the authority to
define the meaning of ``VOC'' and, hence, what compounds shall be
treated as VOC for regulatory purposes. The policy of excluding
negligibly reactive compounds from the regulatory definition of VOC was
first laid out in the ``Recommended Policy on Control of Volatile
Organic Compounds'' (42 FR 35314, July 8, 1977) (``1977 Recommended
Policy'') and was supplemented subsequently with the ``Interim Guidance
on Control of Volatile Organic Compounds in Ozone State Implementation
Plans'' (70 FR 54046, September 13, 2005) (``2005 Interim Guidance'').
The EPA uses the reactivity of ethane as the threshold for determining
whether a compound has negligible reactivity. Compounds that are less
reactive than, or equally reactive to, ethane under certain assumed
conditions may be deemed negligibly reactive and, therefore, suitable
for exemption from the regulatory definition of VOC. Compounds that are
more reactive than ethane continue to be considered VOC for regulatory
purposes and, therefore, are subject to control requirements. The
selection of ethane as the threshold compound was based on a series of
smog chamber experiments that underlay the 1977 Recommended Policy.
The EPA has used three different metrics to compare the reactivity
of a specific compound to that of ethane: (i) The rate constant for
reaction with the hydroxyl radical (OH) (known as kOH); (ii)
the maximum incremental reactivity (MIR) on a reactivity per unit mass
basis; and (iii) the MIR expressed on a reactivity per mole basis.
Differences between these three metrics are discussed below.
The kOH is the rate constant of the reaction of the
compound with the OH radical in the air. This reaction is often, but
not always, the first and rate-limiting step in a series of chemical
reactions by which a compound breaks down in the air and contributes to
O3 formation. If this step is slow, the compound will likely
not form O3 at a very fast rate. The kOH values
have long been used by the EPA as metrics of photochemical reactivity
and O3-forming activity, and they were the basis for most of
the EPA's early exemptions of negligibly reactive compounds from the
regulatory definition of VOC. The kOH metric is inherently a
molar-based comparison, i.e., it measures the rate at which molecules
react.
The MIR, both by mole and by mass, is a more updated metric of
photochemical reactivity derived from a computer-based photochemical
model, and it has been used as a metric of reactivity since 1995. This
metric considers the complete O3-forming activity of a
compound over multiple hours and through multiple reaction pathways,
not merely the first reaction step with OH. Further explanation of the
MIR metric can be found in Carter (1994).
The EPA has considered the choice between MIRs with a molar or mass
basis for the comparison to ethane in past rulemakings and guidance. In
the 2005 Interim Guidance, the EPA stated:
[A] comparison to ethane on a mass basis strikes the right balance
between a threshold that is low enough to capture compounds that
significantly affect ozone concentrations and a threshold that is
high enough to exempt some compounds that may usefully substitute
for more highly reactive compounds.
When reviewing compounds that have been suggested for VOC-exempt
status, EPA will continue to compare them to ethane using
kOH expressed on a molar basis and MIR values expressed
on a mass basis.\1\
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\1\ Interim Guidance on Control of Volatile Organic Compounds in
Ozone State Implementation Plans, 2005, US Environmental Protection
Agency, Document # 05-18015 (70 FR 54046). And could be found at
this link: https://www.govinfo.gov/content/pkg/FR-2005-09-13/pdf/05-18015.pdf.
The 2005 Interim Guidance notes that the EPA will consider a
compound to be negligibly reactive if it is equally as or less reactive
than ethane based on either kOH expressed on a molar basis
or MIR values expressed on a mass basis (70 FR 54046).
The molar comparison of MIR is more consistent with the original
smog chamber experiments, which compared equal molar concentrations of
individual VOC, supporting the selection of ethane as the threshold,
[[Page 25173]]
while the mass-based comparison of MIR is consistent with how MIR
values and other reactivity metrics are applied in reactivity-based
emission limits. It is, however, important to note that the mass-based
comparison is less restrictive than the molar-based comparison in that
more compounds would qualify as negligibly reactive.
Given the two goals of the exemption policy articulated in the 2005
Interim Guidance, the EPA believes that ethane continues to be an
appropriate threshold for defining negligible reactivity. And, to
encourage the use of environmentally beneficial substitutions, the EPA
believes that a comparison to ethane on a mass basis strikes the right
balance between a threshold that is low enough to capture compounds
that significantly affect O3 concentrations and a threshold
that is high enough to exempt some compounds that may usefully
substitute for more highly reactive compounds.
The 2005 Interim Guidance also noted that concerns have sometimes
been raised about the potential impact of a VOC exemption on
environmental endpoints other than O3 concentrations,
including fine particle formation, air toxics exposures, stratospheric
O3 depletion, and climate change. The EPA has recognized,
however, that there are existing regulatory or non-regulatory programs
that are specifically designed to address these issues, and the EPA
continues to believe in general that the impacts of VOC exemptions on
environmental endpoints other than O3 formation can be
adequately addressed by these programs. The VOC exemption policy is
intended to facilitate attainment of the O3 National Ambient
Air Quality Standards (NAAQS), and VOC exemption decisions will
continue to be based primarily on consideration of a compound's
contribution to O3 formation. However, if the EPA determines
that a particular VOC exemption is likely to result in a significant
increase in the use of a compound and that the increased use would pose
a significant risk to human health or the environment that would not be
addressed adequately by existing programs or policies, then the EPA may
exercise its judgment accordingly in deciding whether to grant an
exemption.
B. Petition To List HFO-1336mzz(E) as an Exempt Compound
The Chemours Company submitted a petition to the EPA on November
30, 2016, requesting that (2E)-1,1,1,4,4,4-hexafluorobut-2-ene (HFO-
1336mzz(E); CAS number 66711-86-2) be exempted from the regulatory
definition of VOC. The petition was based on the argument that HFO-
1336mzz(E) has low reactivity (i.e., 0.011 g of O3/g of HFO-
1336mzz(E)) relative to the MIR of ethane (0.28 g O3/g). The
petitioner indicated that HFO-1336mzz(E) may be used in a variety of
applications in foam expansion or blowing agents where it has
significant performance and energy-saving advantages. Chemours has
developed HFO-1336mzz(E) to support reductions in emissions of
greenhouse gases (GHGs). The global warming potentials GWP for HFO-
1336mzz(E) are estimated as 26, 7, and 2 for time horizons of 20, 100,
and 500 years, respectively as estimated by (Osterstrom et al., 2017).
The World Meteorological Organization provided a 100-year GWP of 16 in
its scientific assessment of O3 depletion under the global
ozone research and monitoring project.\2\ Hence, HFO-1336mzz(E) can
serve as a replacement for several higher global warming potential
(>700 GWP) compounds for use in polyurethane rigid insulating foams,
among others, many of which were removed from Significant New
Alternatives Policy (SNAP) acceptable lists beginning on January 1,
2017, or January 1, 2020. The Petitioner stated that manufacturers and
formulators of polyurethane foams and refrigeration equipment need
access to HFO-1336mzz(E) to meet VOC limits on their products without
impairing performance.
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\2\ WMO, 2018. World Meteorological Organization, Scientific
Assessment of Ozone Depletion: 2018, Global Ozone Research and
Monitoring Project--Report No. 58, 588 pp., Geneva, Switzerland,
2018. Available online at: https://ozone.unep.org/sites/default/files/2019-05/SAP-2018-Assessment-report.pdf.
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To support its petition, Chemours referenced several documents,
including one peer-reviewed journal article on HFO-1336mzz(E) reaction
rates (Osterstrom et al., 2017). Chemours also provided a supplemental
technical report on the MIR of HFO-1336mzz(E) (Carter, 2011a). Per this
report, the MIR of HFO-1336mzz(E) is 0.011 g O3/g HFO-
1336mzz(E) on the mass-based MIR scale. This reactivity rate is much
lower than that of ethane (0.28 g O3/g ethane). The
reactivity rate kOH for the gas-phase reaction of OH
radicals with HFO-1336mzz(E) (kOH) has been measured to be
1.72 0.42 x 10-\13\ centimeter (cm)\3\/
molecule-seconds at ~300 degrees Kelvin (K) (Osterstrom et al., 2017).
This kOH rate is lower than that of ethane (kOH
of ethane = 2.4 x 10-\13\ cm\3\/molecule-sec at ~298 K) even
when uncertainty is considered and, therefore, suggests that HFO-
1336mzz(E) is less or equally reactive than ethane. In most cases,
chemicals with high kOH values also have high MIR values,
but for HFO-1336mzz(E), the products that are formed in subsequent
reactions are expected to be poly fluorinated compounds, which do not
contribute to O3 formation (Osterstrom et al., 2017; Carter
2011a). Based on the current scientific understanding of
tetrafluoroalkene reactions in the atmosphere, it is unlikely that the
actual O3 impact on a mass basis would equal or exceed that
of ethane in the scenarios used to calculate VOC reactivity in
Osterstrom et al. (2017), in line with Baasandorj et al. (2011) and
Carter (2011a).
To address the potential for stratospheric O3 impacts,
the petitioner contended that, because the atmospheric lifetime of HFO-
1336mzz(E) due to loss by OH reaction was estimated to be relatively
short and it does not contain chlorine or bromine, it is not expected
to contribute to the depletion of the stratospheric O3 layer
(Osterstrom et al., 2017; Baasandorj et al., 2011).
III. The EPA's Assessment of the Petition
The EPA is proposing to respond to the petition to revise the EPA's
regulatory definition of VOC for exemption of HFO-1336mzz(E). This
action is based on consideration of the compound's low contribution to
tropospheric O3 and the low likelihood of risk to human
health or the environment, including stratospheric O3
depletion, toxicity, and climate change. Additional information on
these topics is provided in the following sections.
A. Contribution to Tropospheric Ozone Formation
As noted in studies cited by the petitioner, HFO-1336mzz(E) has a
MIR value of 0.011 g O3/g VOC for ``averaged conditions,''
versus 0.28 g O3/g VOC for ethane (Carter, 2011). Therefore,
the EPA considers HFO-1336mzz(E) to be negligibly reactive and eligible
for VOC-exempt status in accordance with the Agency's long-standing
policy that compounds should so qualify where either reactivity metric
(kOH expressed on a molar basis or MIR expressed on a mass
basis) indicates that the compound is less reactive than ethane. While
the overall atmospheric reactivity of HFO-1336mzz(E) was not studied in
an experimental smog chamber, the chemical mechanism derived from other
chamber studies (Carter, 2011) was used to model the complete formation
of O3 for an entire single day under realistic atmospheric
conditions (Carter, 2011a). Therefore, the EPA believes that the MIR
value calculated in the Carter study submitted by the petitioner is
reliable as
[[Page 25174]]
it was supported by Osterstrom et al. (2017).
Table 2 presents three reactivity metrics for HFO-1336mzz(E) as
they compare to ethane.
Table 2--Reactivities of Ethane and HFO-1336mzz(E)
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Maximum
incremental Maximum
kOH (cm\3\/molecule- reactivity incremental
Compound sec) (MIR) (g O3/ reactivity
mole VOC) (MIR) (g O3/g
VOC)
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Ethane................................................. 2.4 x 10-\13\ 8.4 0.28
HFO-1336mzz(E)......................................... 1.72 x 10-\13\ 1.8 0.011
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Notes:
kOH value at 298 K for ethane is from Atkinson et al. (2006; page 3626).
kOH value at 300 K for HFO-1336mzz(E) is from Osterstrom (2017) and Baasandorj (2011).
Mass-based MIR value (g O3/g VOC) of ethane is from Carter (2011).
Mass-based MIR value (g O3/g VOC) of HFO-1336mzz(E) is from a supplemental report by Carter (2011a).
Molar-based MIR (g O3/mole VOC) values were calculated from the mass-based MIR (g O3/g VOC) values using the
number of moles per gram of the relevant organic compound.
The reaction rate of HFO-1336mzz(E) with the OH radical
(kOH) has been measured to be 1.72 x 10-13 cm\3\/
molecule-sec (Osterstrom et al., 2017); other reactions with
O3 and the nitrate radical were negligibly small. The
corresponding reaction rate of ethane with OH is 2.4 x 10-13
cm\3\/molecule-sec (Atkinson et al., 2006). The data in Table 2 show
that HFO-1336mzz(E) has a lower kOH value than ethane,
meaning that it initially reacts slower or as fast in the atmosphere as
ethane. However, the resulting unsaturated fluorinated compounds in the
atmosphere are short lived and react more slowly to form O3
(Osterstrom et al., 2017; Baasandorj et al., 2011). The mass-based MIR
is 0.011 g O3/g VOC and much lower than that of ethane.
A molecule of HFO-1336mzz(E) is much less reactive than a molecule
of ethane in terms of complete O3-forming activity, as shown
by the molar-based MIR (g O3/mole VOC) values. Likewise, one
gram of HFO-1336mzz(E) has a lower capacity than one gram of ethane to
form O3 in terms of a mass-based MIR. Thus, following the
2005 Interim Guidance, the EPA proposes to find HFO-1336mzz(E) to be
eligible for exemption from the regulatory definition of VOC based on
both the molar- and mass-based MIR.
B. Potential Impacts on Other Environmental Endpoints
The EPA's proposed decision to exempt HFO-1336mzz(E) from the
regulatory definition of VOC is based on our findings above. However,
as noted in the 2005 Interim Guidance, the EPA reserves the right to
exercise its judgment in certain cases where an exemption is likely to
result in a significant increase in the use of a compound and a
subsequent significantly increased risk to human health or the
environment. In this case, the EPA does not find that exemption of HFO-
1336mzz(E) would result in an increase of risk to human health or the
environment, regarding stratospheric O3 depletion, toxicity,
and climate change. Additional information on these topics is provided
in the following sections.
1. Contribution to Stratospheric Ozone Depletion
The SNAP program is the EPA's program to evaluate and regulate
substitutes for end-uses historically using O3-depleting
chemicals. Under section 612(c) of the CAA, the EPA is required to
identify and publish lists of acceptable and unacceptable substitutes
for class I or class II O3-depleting substances. Per the
SNAP program findings, the ODP of HFO-1336mzz(E) is zero. The SNAP
program has listed HFO-1336mzz(E) as an acceptable substitute for a
number of foam-blowing end-uses provided in 85 FR 79863, December 11,
2020 (USEPA, 2020).
HFO-1336mzz(E) is unlikely to contribute to the depletion of the
stratospheric O3 layer. The O3 depletion
potential (ODP) of HFO-1336mzz(E) is expected to be negligible based on
several lines of evidence: the absence of chlorine or bromine in the
compound and the atmospheric reactions described in Carter (2008).
Because HFO-1336mzz(E)'s atmospheric lifetime is short relative to the
time scale for mixing within the troposphere, it will decay before it
has a chance to reach the stratosphere and, thus, will not participate
in O3 destruction.
2. Toxicity
Based on screening assessments of the health and environmental
risks of HFO-1336mzz(E), the SNAP program anticipated that users will
be able to use the compound without significantly greater health risks
than presented by the use of other available substitutes for the same
end uses (USEPA, 2020).
The EPA anticipates that HFO-1336mzz(E) will be used consistent
with the recommendations specified in the manufacturer's safety data
sheet (SDS) (Chemours, 2016). According to the SDS, potential health
effects from inhalation of HFO-1336mzz(E) include skin or eye
irritation or frostbite. Exposure to high concentrations of HFO-
1336mzz(E) from misuse or intentional inhalation abuse may cause
irregular heartbeat. In addition, HFO-1336mzz(E) could cause
asphyxiation if air is displaced by vapors in a confined space. The
Workplace Environmental Exposure Limit (WEEL) committee of the
Occupational Alliance for Risk Science (OARS) reviewed available animal
toxicity data and recommends a WEEL for the workplace of 400 parts per
million (ppm) (2680 mg/m\3\) \3\ time-weighted average (TWA) for an 8-
hour workday, as later published in 2019 in Toxicology and Industrial
Health (``Trans-1,1,1,4,4,4-hexafluoro-2-butene,'' 2019).\4\ This WEEL
was derived based on reduced male body weight gain in the 13-week rat
inhalation toxicity study (TNO, 2016a, and TNO, 2016b), based on the
point of departure of NOAEL of 7500 ppm. This was also the NOAEL for
the developmental toxicity study where developmental effects were only
[[Page 25175]]
observed at maternally toxic levels. The EPA anticipates that users
will be able to meet the WEEL and address potential health risks by
following requirements and recommendations in the SDS and other safety
precautions common to the refrigeration and air conditioning industry.
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\3\ Occupational Alliance for Risk Science (OARS-WEELs)- HFO-
1336mzz(E), 2018: https://www.tera.org/OARS/PDF_documents/03_trans-1-1-1-4-4-4-hexafluoro-2-butene-(hfo-1336mzz-e).pdf.
\4\ Trans-1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336mzz(E))
(2018). (2019). Toxicology and Industrial Health, 35(3), 204-210.
https://doi.org/10.1177/0748233719825529.
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HFO-1336mzz(E) is not regulated as a hazardous air pollutant (HAP)
under title I of the CAA. Also, it is not listed as a toxic chemical
under section 313 of the Emergency Planning and Community Right-to-Know
Act (EPCRA).
The Toxic Substances Control Act (TSCA) gives the EPA authority to
assess and prevent potential unreasonable risks to human health and the
environment before a new chemical substance is introduced into
commerce. Section 5 of TSCA requires manufacturers and importers to
notify the EPA before manufacturing or importing a nonexempt new
chemical substance by submitting a Premanufacture Notice (PMN) prior to
the manufacture (including import) of the chemical substance. Under the
TSCA New Chemicals Program, the EPA then assesses whether an
unreasonable risk may, or will, be presented by the expected
manufacturing, processing, distribution in commerce, use, and disposal
of the new substance. Based on its review of a PMN and a Significant
New Use Notice (SNUN) for HFO-1336mzz(E), the EPA has determined that
use of HFO-1336mzz(E) in consumer products or use other than as
described in the PMN and SNUN, may cause serious chronic health
effects. To address concerns identified during the PMN review of HFO-
1336mzz(E), the EPA issued a Significant New Use Rule (SNUR) under TSCA
on May 16, 2016, to require submission of a SNUN to the EPA at least 90
days before manufacturing or processing of HFO-1336mzz(E) for any uses
in consumer products or any use other than as described in the PMN (81
FR 30451, 30462, May 16, 2016). The required notification will provide
the EPA with the opportunity to evaluate the intended use before it
occurs and, if necessary, to prohibit or limit that activity to protect
against an unreasonable risk. The EPA received a SNUN for a significant
new use of HFO-1336mzz(E) in 2017 and modified the SNUR in June 2021
based on its determination for the SNUN (86 FR 30210, 30215, June 7,
2021).\5\ The EPA, therefore, believes that existing programs address
the risk of toxicity associated with the use of HFO-1336mzz(E).
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\5\ https://www.govinfo.gov/content/pkg/FR-2021-06-07/html/2021-11768.htm.
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The EPA recognizes that both HFO-1336mmz(E) and its atmospheric
breakdown product trifluoroacetic acid (TFA) are members of the broad
class of compounds known as per- and poly-fluoroalkyl substances
(PFAS), even though they are not among the PFAS currently listed or
targeted for specific Agency action. Many PFAS are highly mobile in
various media, some are volatile and can be transported long distances
in air and/or in water and widely distributed in the environment. Some
studies suggest that PFAS emitted to air can result in human exposures
in other media such as source/surface or drinking waters even though
the emissions origin may be distant from receptor water bodies.\6\ Some
PFAS are persistent in the environment and in the human body and can
accumulate over time. There is evidence that exposure to certain PFAS
can lead to adverse human health effects (e.g., low infant birth
weights, immune system effects, cancer, and thyroid disruption).
Numerous states have developed health-based (e.g., drinking water)
standards for various PFAS. The Environmental Effects Assessment Panel
for the Montreal Protocol (EEAP) has considered the production of TFA
as a breakdown product of HFCs and HFOs and has found, ``Projected
future increased loadings of TFA to playas, land-locked lakes, and the
oceans due to continued use of HCFCs, HFCs, and replacement products
such as HFOs are still judged to present negligible risks for aquatic
organisms and humans.'' \7\ In its most recent assessment report (2018
Assessment Report), EEAP found, ``Overall, there is no new evidence
that contradicts the conclusion of our previous Assessments that
exposure to current and projected concentrations of salts of TFA in
surface waters present a minimal risk to the health of humans and the
environment.'' \8\
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\6\ https://pubs.acs.org/doi/abs/10.1021/acs.est.0c06580.
\7\ UNEP, 2015. Environmental Effects Of Ozone Depletion And Its
Interactions With Climate Change: 2014 Assessment of the Montreal
Protocol. United Nations Environment Programme (UNEP), Nairobi. This
document accessible at: https://ozone.unep.org/sites/default/files/2019-05/eeap_report_2014.pdf.
\8\ UNEP, 2019. Environmental Effects and Interactions of
Stratospheric Ozone Depletion, UV Radiation, and Climate Change:
2018 Assessment Report of the Montreal Protocol. United Nations
Environment Programme (UNEP), Nairobi. This document accessible at:
https://ozone.unep.org/sites/default/files/2019-04/EEAP_assessment-report-2018%20%282%29.pdf.
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3. Contribution to Climate Change
The Intergovernmental Panel on Climate Change (IPCC) Fifth
Assessment Report (IPCC AR5) does not provide an estimate for HFO-
1336mzz(E) global warming potential (GWP).\9\ The HFO-1336mzz(E) GWP on
a 100-year time horizon was calculated to be 7 in 1 study by Osterstrom
et al. (2017) and 32 (atmospherically well-mixed) and 14 (lifetime-
adjusted) in another study by Baasandorj et al. (2018). However, the
WMO (2018) calculated the 100-year GWP for HFO-1336mzz(E) as 16.
Species with double bonds assembled in the Intergovernmental Panel on
Climate Change Fifth Assessment Report (Table 8.A.1) indicate lower GWP
than species without a double bond. However, the GWP of 14 approximated
by (Baasandorj et al., 2018), and the gas-phase degradation of HFO-
1336-mzz(E) is not expected to lead to a significant formation of
atmospherically long-lived species. According to the SNAP rule, HFO-
1336mzz(E)'s GWP of 16 is lower than those of some of the substitutes
in a variety of foam blowing and refrigeration end-uses, solvents, and
aerosol propellants (USEPA, 2020). HFO-1336mzz(E) was developed to
replace other chemicals used for similar end-uses with GWP ranging from
1 to 1,300 such as the refrigerant 1,1,1,2-tetrafluoroethane (R-134a),
among others. The petitioner claims that HFO-1336mzz(E) is a better
alternative to other substitutes in foam expansion or blowing agents
for use in polyurethane rigid insulating foams. Specifically, HFO-
1336mzz(E) will provide significant performance and energy saving
advantages and reduce climate change impacts both directly by its
relatively low GWP and indirectly by decreasing energy consumption
throughout the lifecycle of insulated foams in several applications.
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\9\ IPCC, 2013: Climate Change 2013: Chapter 8, Myhre, G., D.
Shindell, F.-M. Br[eacute]on, W. Collins, J. Fuglestvedt, J. Huang,
D. Koch, J.-F. Lamarque, D. Lee, B. Mendoza, T. Nakajima, A. Robock,
G. Stephens, T. Takemura and H. Zhang, 2013: Anthropogenic and
Natural Radiative Forcing. In: Climate Change 2013: The Physical
Science Basis. Contribution of Working Group I to the Fifth
Assessment Report of the Intergovernmental Panel on Climate Change
[Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J.
Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)].
Cambridge University Press, Cambridge, United Kingdom and New York,
NY, USA. https://www.ipcc.ch/site/assets/uploads/2018/02/WG1AR5_Chapter08_FINAL.pdf.
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C. Conclusions
The EPA proposes that HFO-1336mzz(E) is negligibly reactive with
respect to its contribution to tropospheric O3 formation
and, thus,
[[Page 25176]]
may be exempted from the EPA's definition of VOC in 40 CFR 51.100(s).
HFO-1336mzz(E) has been listed as acceptable for use as a blowing agent
in several end-uses under the SNAP program (USEPA, 2020). The EPA has
also determined that exemption of HFO-1336mzz(E) from the regulatory
definition of VOC will not result in an increase of risk to human
health and the environment, and, to the extent that use of this
compound does have impacts on other environmental endpoints, those
impacts are adequately managed by existing programs. For example, HFO-
1336mzz(E) has a similar or lower stratospheric O3 depletion
potential than available substitutes in those end-uses, and the
toxicity risk from using HFO-1336mzz(E) is not significantly greater
than the risk from using other available alternatives for the same
uses. The EPA has concluded that non-tropospheric O3-related
risks associated with potential increased use of HFO-1336mzz(E) are
adequately managed by SNAP. The EPA does not expect significant use of
HFO-1336mzz(E) in applications not covered by the SNAP program. To the
extent that the compound is used in other applications not already
reviewed under SNAP or under the New Chemicals Program under TSCA, the
SNUR in place under TSCA requires that any significant new use of a
chemical be reported to the EPA using a Significant New Use Notice
(SNUN). Any significant new use of HFO-1336mzz(E) would, thus, need to
be evaluated by the EPA, and the EPA will continually review the
availability of acceptable substitute chemicals under the SNAP program.
This class of PFAS is highly varied, and variations in structure
may result in (yet unknown) differences in environmental mobility and
toxicity. The agency's ongoing work in PFAS is based on the recent PFAS
Strategic Roadmap: EPA's Commitments to Action 2021-2024, which lays
out an agenda and actions that have yet to be fully realized. Part of
that plan is to better understand the environmental mobility, toxicity,
and treatability of various congeners. There is much that we do not
know about PFAS in general and for specific compounds. Therefore, EPA
is seeking public comment on whether and how EPA should consider
information on and properties of PFAS compounds beyond those properties
related to the VOC exemption program and how it might impact the VOC
delisting decision.
IV. Proposed Action
The EPA is responding to the petition by proposing to revise its
regulatory definition of VOC at 40 CFR 51.100(s) to add HFO-1336mzz(E)
to the list of compounds that are exempt from the regulatory definition
of VOC because it is less reactive than ethane based on a comparison of
mass-based MIR and molar-based MIR metrics and is, therefore,
considered negligibly reactive. As a result of this action, if an
entity uses or produces this compound and is subject to the EPA
regulations limiting the use of VOC in a product, limiting the VOC
emissions from a facility, or otherwise controlling the use of VOC for
purposes related to attaining the O3 NAAQS, this compound
will not be counted as a VOC in determining whether these regulatory
obligations have been met. This action would affect whether this
compound is considered a VOC for state regulatory purposes to reduce
O3 formation, if a state relies on the EPA's regulatory
definition of VOC. States are not obligated to exclude from control as
a VOC those compounds that the EPA has found to be negligibly reactive.
However, no state may take credit for controlling this compound in its
O3 control strategy. Consequently, reductions in emissions
for this compound will not be considered or counted in determining
whether states have met the rate of progress requirements for VOC in
State Implementation Plans or in demonstrating attainment of the
O3 NAAQS.
V. Statutory and Executive Order Reviews
A. Executive Order 12866: Regulatory Planning and Review and Executive
Order 13563: Improving Regulation and Regulatory Review
This action is not a significant regulatory action and was,
therefore, not submitted to the Office of Management and Budget (OMB)
for review.
B. Paperwork Reduction Act (PRA)
This action does not impose an information collection burden under
the PRA. It does not contain any recordkeeping or reporting
requirements.
C. Regulatory Flexibility Act (RFA)
I certify that this action will not have a significant economic
impact on a substantial number of small entities under the RFA. This
action will not impose any requirements on small entities. This action
removes HFO-1336mzz(E) from the regulatory definition of VOC and,
thereby, relieves manufacturers, distributers, and users of the
compound from tropospheric O3 requirements to control
emissions of the compound.
D. Unfunded Mandates Reform Act (UMRA)
This action does not contain any unfunded mandate as described in
UMRA, 2 U.S.C. 1531-1538, and does not significantly or uniquely affect
small governments. This action imposes no enforceable duty on any
state, local or tribal governments, or the private sector.
E. Executive Order 13132: Federalism
This action does not have federalism implications. It will not have
substantial direct effects on the states, on the relationship between
the national government and the states, or on the distribution of power
and responsibilities among the various levels of government.
F. Executive Order 13175: Consultation and Coordination With Indian
Tribal Governments
This action does not have tribal implications, as specified in
Executive Order 13175. This proposed rule removes HFO-1336mzz(E) from
the regulatory definition of VOC and, thereby, relieves manufacturers,
distributers, and users from tropospheric O3 requirements to
control emissions of the compound. Thus, Executive Order 13175 does not
apply to this action.
G. Executive Order 13045: Protection of Children From Environmental
Health and Safety Risks
This action is not subject to Executive Order 13045, because it is
not economically significant as defined in Executive Order 12866, and
because the EPA does not believe the environmental health or safety
risks addressed by this action present a disproportionate risk to
children. Since HFO-1336mzz(E) is utilized in specific industrial
applications where children are not present and dissipates quickly
(e.g., lifetime of 22 days) with short-lived end products, there is no
exposure or disproportionate risk to children. This action removes HFO-
1336mzz(E) from the regulatory definition of VOC and, thereby, relieves
manufacturers, distributers, and users from tropospheric O3
requirements to control emissions of the compound.
H. Executive Order 13211: Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution or Use
This action is not subject to Executive Order 13211, because it is
not a
[[Page 25177]]
significant regulatory action under Executive Order 12866.
I. National Technology Transfer and Advancement Act (NTTAA)
This rulemaking does not involve technical standards.
J. Executive Order 12898: Federal Actions To Address Environmental
Justice in Minority Populations and Low-Income Populations
The EPA believes that this action does not have disproportionately
high and adverse human health or environmental effects on minority
populations, low-income populations and/or indigenous peoples, as
specified in Executive Order 12898 (59 FR 7629, February 16, 1994).
This action removes HFO-1336mzz(E) from the regulatory definition of
VOC and, thereby, relieves manufacturers, distributers, and users of
the compound from tropospheric O3 requirements to control
emissions of the compound.
K. Judicial Review
Under section 307(b)(1) of the CAA, petitions for judicial review
of this action must be filed in the United States Court of Appeals for
the District of Columbia Circuit Court within 60 days from the date the
proposed action is published in the Federal Register. Filing a petition
for review by the Administrator of this proposed action does not affect
the finality of this action for the purposes of judicial review nor
does it extend the time within which a petition for judicial review
must be filed and shall not postpone the effectiveness of such action.
Thus, any petitions for review of this action related to the exemption
of HFO-1336mzz(E) from the regulatory definition of VOC must be filed
in the Court of Appeals for the District of Columbia Circuit within 60
days from the date proposed action is published in the Federal
Register.
VII. References
Atkinson, R., Baulch, D.L., Cox, R.A., Crowley, J.N., Hampson, Jr.,
R.F., Hynes, R.G., Jenkin, M.E., Kerr, J.A., Rossi, M.J., and Troe,
J. (2006) Evaluated kinetic and photochemical data for atmospheric
chemistry: Volume II--gas phase reactions of organic species. Atmos.
Chem. Phys. 6: 3625-4055.
Baasandorj, M., Ravishankara, A.R., Burkholder, J.B. (2011)
Atmospheric chemistry of (Z)-CF3CH[boxH]CHCF3: OH radical reaction
rate coefficient and global warming potential. J Phys Chem A. 2011
Sep 29;115(38):10539-49. doi: 10.1021/jp206195g.
Baasandorj, M., Marshall, P., Waterland, R.L., Ravishankara, A.R. &
Burkholder, J.B. Rate Coefficient Measurements and Theoretical
Analysis of the OH + (E)-CF3CH[boxH]CHCF3 Reaction. The Journal of
Physical Chemistry A 122, 4635-4646, doi:10.1021/acs.jpca.8b02771
(2018).
Carter, W.P.L. (1994) Development of ozone reactivity scales for
volatile organic compounds. J. Air Waste Manage, 44: 881-899.
Carter, W.P.L. (2008) Reactivity Estimates for Selected Consumer
Product Compounds, Final Report to California Air Resources Board
Contract No. 06-408, February 19, 2008. http://www.arb.ca.gov/research/reactivity/consumer_products.pdf.
Carter, W.P.L. (2011) SAPRC Atmospheric Chemical Mechanisms and VOC
Reactivity Scales, at http://www.engr.ucr.edu/~carter/SAPRC/. Last
updated in Sept. 14, 2013. Tables of Maximum Incremental Reactivity
(MIR) Values available at http://www.arb.ca.gov/regact/2009/mir2009/mir2009.htm. May 11, 2011.
Carter, W.P.L. (2011a) Estimation of the ground-level atmospheric
ozone formation potentials of Cis 1,1,1,4,4,4-HexaFluoro-2-Butene,
August 8, 2011.
Chemours. (2016) CD-59 Foam Expansion Agent Safety Data Sheet.
Version 4.1. The Chemours Company FC, LLC, Wilmington, DE December
2016.
Osterstrom, F.F., Andersen, S.T., S[oslash]lling, T.I., Nielsena, O
J., and Andersen, M.P.S. (2017) Atmospheric chemistry of Z- and E-
CF3CH--CHCF3: Phys.Chem.Chem.Phys., 2017, 19, 735
TNO (Netherlands Organization for Applied Scientific Research).
(2016a) Sub-chronic (13-week) inhalation toxicity study with HFO-
1336mzz(E) in rats. Report No. V20686. TNO Company, Netherlands.
Unpublished report.
TNO (Netherlands Organization for Applied Scientific Research).
(2016b) Inhalation prenatal developmental toxicity study with HFO-
1336mzz(E)in rats. Report No. V20685. TNO Company, Netherlands.
Pitts, J.N. Jr., Winer, A.M., Aschmann, S.M., Carter, W.P.L., and
Atkinson, K. (1983), Experimental Protocol for Determining Hydroxyl
Radical Reaction Rate Constants Environmental Science Research
Laboratory, ORD, USEPA. EPA600/3-82-038.
USEPA, 2020. Protection of Stratospheric Ozone: Determination 36 for
Significant New Alternatives Policy Program December 11, 2020. 85 FR
79863. Available online at: https://www.govinfo.gov/content/pkg/FR-2020-12-11/pdf/2020-23861.pdf.
List of Subjects in 40 CFR Part 51
Environmental protection, Administrative practice and procedure,
Air pollution control, Ozone, Reporting and recordkeeping requirements,
Volatile organic compounds.
Michael S. Regan,
Administrator.
For reasons stated in the preamble, part 51 of chapter I of title
40 of the Code of Federal Regulations is proposed to be amended as
follows:
PART 51--REQUIREMENTS FOR PREPARATION, ADOPTION, AND SUBMITTAL OF
IMPLEMENTATION PLANS
0
1. The authority citation for part 51 continues to read as follows:
Authority: 23 U.S.C. 101; 42 U.S.C. 7401-7671q.
Subpart F--Procedural Requirements
0
2. Section 51.100 is amended by revising the introductory text of
paragraph (s)(1).
Sec. 51.100 Definitions.
* * * * *
(s) * * *
(1) This includes any such organic compound other than the
following, which have been determined to have negligible photochemical
reactivity: Methane; ethane; methylene chloride (dichloromethane);
1,1,1-trichloroethane (methyl chloroform); 1,1,2-trichloro-1,2,2-
trifluoroethane (CFC-113); trichlorofluoromethane (CFC-11);
dichlorodifluoromethane (CFC-12); chlorodifluoromethane (HCFC-22);
trifluoromethane (HFC-23); 1,2-dichloro 1,1,2,2-tetrafluoroethane (CFC-
114); chloropentafluoroethane (CFC-115); 1,1,1-trifluoro 2,2-
dichloroethane (HCFC-123); 1,1,1,2-tetrafluoroethane (HFC-134a); 1,1-
dichloro 1-fluoroethane (HCFC-141b); 1-chloro 1,1-difluoroethane (HCFC-
142b); 2-chloro-1,1,1,2-tetrafluoroethane (HCFC-124); pentafluoroethane
(HFC-125); 1,1,2,2-tetrafluoroethane (HFC-134); 1,1,1-trifluoroethane
(HFC-143a); 1,1-difluoroethane (HFC-152a); parachlorobenzotrifluoride
(PCBTF); cyclic, branched, or linear completely methylated siloxanes;
acetone; perchloroethylene (tetrachloroethylene); 3,3-dichloro-
1,1,1,2,2-pentafluoropropane (HCFC-225ca); 1,3-dichloro-1,1,2,2,3-
pentafluoropropane (HCFC-225cb); 1,1,1,2,3,4,4,5,5,5-decafluoropentane
(HFC 43-10mee); difluoromethane (HFC-32); ethylfluoride (HFC-161);
1,1,1,3,3,3-hexafluoropropane (HFC-236fa); 1,1,2,2,3-pentafluoropropane
(HFC-245ca); 1,1,2,3,3-pentafluoropropane (HFC-245ea); 1,1,1,2,3-
pentafluoropropane (HFC-245eb); 1,1,1,3,3-pentafluoropropane (HFC-
245fa); 1,1,1,2,3,3-hexafluoropropane (HFC-236ea); 1,1,1,3,3-
pentafluorobutane (HFC-365mfc); chlorofluoromethane (HCFC-31); 1
chloro-1-fluoroethane (HCFC-151a); 1,2-dichloro-1,1,2-trifluoroethane
(HCFC-123a); 1,1,1,2,2,3,3,4,4-nonafluoro-4-methoxy-butane
(C4F9OCH3 or HFE-7100); 2-
(difluoromethoxymethyl)-
[[Page 25178]]
1,1,1,2,3,3,3-heptafluoropropane
((CF3)2CFCF2OCH3); 1-
ethoxy-1,1,2,2,3,3,4,4,4-nonafluorobutane
(C4F9OC2H5 or HFE-7200); 2-
(ethoxydifluoromethyl)-1,1,1,2,3,3,3-heptafluoropropane
((CF3)2CFCF2OC2H5
); methyl acetate; 1,1,1,2,2,3,3-heptafluoro-3-methoxy-propane (n-
C3F7OCH3, HFE-7000); 3-ethoxy-1,1,1,2,3,4,4,5,5,6,6,6-dodecafluoro-2-
(trifluoromethyl) hexane (HFE-7500); 1,1,1,2,3,3,3-heptafluoropropane
(HFC 227ea); methyl formate (HCOOCH3); 1,1,1,2,2,3,4,5,5,5-decafluoro-
3-methoxy-4-trifluoromethyl-pentane (HFE-7300); propylene carbonate;
dimethyl carbonate; trans-1,3,3,3-tetrafluoropropene;
HCF2OCF2H (HFE-134);
HCF2OCF2OCF2H (HFE-236cal2);
HCF2OCF2CF2OCF2H (HFE-
338pcc13);
HCF2OCF2OCF2CF2OCF2
H (H-Galden 1040x or H-Galden ZT 130 (or 150 or 180)); trans 1-chloro-
3,3,3-trifluoroprop-1-ene; 2,3,3,3-tetrafluoropropene; 2-amino-2-
methyl-1-propanol; t-butyl acetate; 1,1,2,2- Tetrafluoro -1-(2,2,2-
trifluoroethoxy) ethane; cis-1,1,1,4,4,4-hexafluorobut-2-ene (HFO-
1336mzz-Z); trans-1,1,1,4,4,4-hexafluorobut-2-ene (HFO-1336mzz(E)); and
perfluorocarbon compounds which fall into these classes:
* * * * *
[FR Doc. 2022-08922 Filed 4-27-22; 8:45 am]
BILLING CODE 6560-50-P