[Federal Register Volume 88, Number 26 (Wednesday, February 8, 2023)]
[Rules and Regulations]
[Pages 8226-8233]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-02384]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 51
[EPA-HQ-OAR-2021-0420; FRL-8371-01-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: Final rule.
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SUMMARY: On April 28, 2022, the U.S. Environmental Protection Agency
(EPA) published a proposed rule seeking comments in response to a
petition requesting the revision of the EPA's regulatory definition of
volatile organic compounds (VOC) to exempt trans-1,1,1,4,4,4-
hexafluorobut-2-ene (also known as HFO-1336mzz(E); CAS number 66711-86-
2). The EPA is now taking final action to revise the regulatory
definition of VOC under the Clean Air Act (CAA). This final action adds
HFO-1336mzz(E) to the list of compounds excluded from the regulatory
definition of VOC on the basis that this compound makes a negligible
contribution to tropospheric ozone (O3) formation.
DATES: This final rule is effective on April 10, 2023.
ADDRESSES: The EPA has established a docket for this action under
Docket ID No. EPA-HQ-OAR-2021-0420. All documents in the docket are
listed on the https://www.regulations.gov website. Although listed in
the index, some information is not publicly available, e.g., CBI or
other information whose disclosure is restricted by statute. Certain
other material, such as copyrighted materials, is not placed on the
internet and will be publicly available only in hard copy form.
Publicly available docket materials are available electronically
through https://www.reglatons.gov.
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:
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. Response to Comments and Conclusion
IV. Final 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)
[[Page 8227]]
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. Congressional Review Act (CRA)
L. Judicial Review
VI. References
I. Does this action apply to me?
Entities potentially affected by this final 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.
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.
[[Page 8228]]
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 that a comparison to ethane's
MIR on the mass basis will strike the right balance between a threshold
that is low enough to capture chemicals that significantly effect ozone
formation and the threshold that is high enough to allow for the
exemption of some other chemicals that may usefully substitute for more
reactive compounds. And that EPA will continue to compare chemicals to
ethane using kOH expressed in molar basis and MIR values
expressed on a mass basis during the review of suggested chemicals for
VOC-exempt status.\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
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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,
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
ethane). 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 (GWPs) 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 polyfluorinated 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
[[Page 8229]]
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
On April 28, 2022, the EPA published a proposed rulemaking (87 FR
25170) seeking comments in response to the petition to revise the EPA's
regulatory definition of VOC for exemption of HFO-1336mzz(E). The EPA
is taking final action to respond to the petition by exempting HFO-
1336mzz(E) from the regulatory definition of VOC. 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 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
Compound kOH (cm\3\/ reactivity (MIR) incremental
molecule-sec) (g O3/mole VOC) reactivity (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 for ethane is at 298 K and from Atkinson et al. (2006; page 3626).
kOH value for HFO-1336mzz(E) is at 300 K and 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 than 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 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, with
regard to 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
[[Page 8230]]
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
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 persistent 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)'s GWP.\9\
[[Page 8231]]
The HFO-1336mzz(E) GWP on a 100-year time horizon was calculated to be
7 in one 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.
Given the presence of a double bond in the HFO-1336mzz(E) molecule, its
atmospheric degradation is accelerated, and its atmospheric lifetime is
reduced, thereby reducing its long-term GWP. According to the SNAP
rule, HFO-1336mzz(E)'s GWP of 16 is lower than the GWPs of some of the
substitutes in a variety of foam blowing and refrigeration, solvent,
and aerosol propellant end-uses (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. Response to Comments and Conclusion
The EPA received two comments by the close of the public comment
period on June 28, 2022, on the notice of proposed rulemaking. However,
no specific issues that are relevant to our action to exempt HFO-
1336mzz(E) were submitted. No negative comments were received on the
proposed action or raised any issues about the PFAS and/or
recommendation to address them under the revision of the VOC
definition. Details on those comments received and the EPA's responses
are provided below.
Comments: The first commenter was the petitioner who supported the
proposed action to exempt HFO-1336mzz(E) from the EPA's definition of
VOC in 40 CFR 51.100(s). The petitioner insisted that PFAS issues were
outside the scope of this rulemaking, referring to other EPA programs
that are currently working to address them. The petitioner also
mentioned EPA's ongoing efforts in defining what PFAS are, and the
agency's testing strategy, adding that HFO-1336mzz(E) is not currently
included in the EPA's working definition of PFAS. The second commenter
submitted similar supporting arguments on behalf of multiple
professional organizations including the U.S. Chamber of Commerce. They
stipulated that this rulemaking is not the proper vehicle for broadly
examining questions about properties of PFAS and their chemistry,
properties that are not related to the VOC exemption program as we
requested in the proposal. They referred to multiple EPA initiatives
underway which will provide a better platform to address PFAS issues,
urging the exemption of HFO-1336-mzz(E) as the focus of this
rulemaking.
Response: The EPA acknowledges the commenters' support to exempt
HFO1336mzz(E) from the EPA's regulatory definition of VOC in 40 CFR
51.100(s).
The commenter is correct that HFO-1336mzz(E) does not meet the
Office of Pollution Prevention and Toxics' (OPPT) working definition of
PFAS.\10\ However, EPA notes that this definition may not be identical
to other definitions of PFAS used within EPA and/or by other
organizations. The term ``PFAS'' has been used broadly by many
organizations for their individual research and/or regulatory needs.
Various programs or organizations have distinct needs or purposes apart
from the proposed TSCA section 8(a)(7) reporting rule, and therefore,
different definitions of the term ``PFAS'' may be appropriate for other
purposes, including this program.\11\ At this time, we do not believe
it is necessary to consider a definition of PFAS that applies to the
VOC exemption process, because the Agency evaluates each chemical
substance on a case-by-case basis against the relevant criteria in the
2005 Interim Guidance.
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\10\ OPPT's proposed rule defined PFAS as ``any chemical
substance or mixture that structurally contains the unit R-(CF2)-
C(F)(R')R''. Both the CF2 and CF moieties are saturated carbons.
None of the R groups (R, R' or R'') can be hydrogen.'' Toxic
Substances Control Act Reporting and Recordkeeping Requirements for
Perfluoroalkyl and Polyfluoroalkyl Substances Posted by the
Environmental Protection Agency, 86 FR 33926, 33937 (proposed on
June 28, 2021).
\11\ See OECD, Reconciling Terminology of the Universe of Per-
and Polyfluoroalkyl Substances: Recommendations and Practical
Guidance p. 8 (July 2021), https://www.oecd.org/officialdocuments/publicdisplaydocumentpdf/?cote=ENV/CBC/MONO(2021)25&docLanguage=En.
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IV. Final Action
The EPA is responding to the petition by revising 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
Additional information about these statutes and Executive Orders
can be found at https://www2.epa.gov/laws-regulations/laws-and-executive-orders.
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 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
[[Page 8232]]
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 final 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. 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 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
Executive Order 12898 (59 FR 7629, February 16, 1994) directs
federal agencies, to the greatest extent practicable and permitted by
law, to make environmental justice part of their mission by identifying
and addressing, as appropriate, disproportionately high, and adverse
human health or environmental effects of their programs, policies, and
activities on minority populations (people of color and/or Indigenous
peoples) and low-income populations.
The EPA believes that the human health and environmental conditions
that exist prior to this action do not result in disproportionate and
adverse effects on people of color, low-income populations, and/or
Indigenous peoples as we found no data available to support the
opposite. Projected effects on the various populations after this
action is implemented are not likely to result in new potentially
disproportionate and adverse effects. We addressed the human health and
environmental risks by this action to the greatest ability feasible,
and those risks will not have potential disproportionately high and
adverse human health or environmental effects on minority, low-income
or indigenous populations (in particular children), because of no
possible exposure. This chemical is used in specific industrial
applications where children are not present. This action was developed
in accordance with agency guidance on environmental justice.
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. It will in fact help states focus on more
photochemically reactive chemicals preventing more formation of Ozone
and consequently more adverse related health and environmental effects.
K. Congressional Review Act (CRA)
This action is subject to the CRA, and the EPA will submit a rule
report to each House of the Congress and to the Comptroller General of
the United States. This action is not a ``major rule'' as defined by 5
U.S.C. 804(2).
L. 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
final action is published in the Federal Register. Filing a petition
for review by the Administrator of this final 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 final action is published in the Federal Register.
VI. 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://
[[Page 8233]]
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,
OJ., 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 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 paragraph (s)(1) introductory
text to read as follows:
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)-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. 2023-02384 Filed 2-7-23; 8:45 am]
BILLING CODE 6560-50-P