Document ID: EPA-HQ-OAR-2019-0698-0080
Agency: epa
Document Type: Proposed Rule
Title: Protection of Stratospheric Ozone: Listing of Substitutes under the Significant New Alternatives Policy Program; Supplemental Proposal
Posted Date: 2021-10-06T04:00Z

[Federal Register Volume 86, Number 191 (Wednesday, October 6, 2021)]
[Proposed Rules]
[Pages 55549-55560]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-21031]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 82

[EPA-HQ-OAR-2019-0698; FRL-7826.1-02-OAR]
RIN 2060-AV31

Protection of Stratospheric Ozone: Listing of Substitutes Under 
the Significant New Alternatives Policy Program; Supplemental Proposal

AGENCY: Environmental Protection Agency (EPA).

ACTION: Supplemental notice of proposed rulemaking.

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SUMMARY: Pursuant to the U.S. Environmental Protection Agency's 
Significant New Alternatives Policy program, the Agency is proposing, 
as an

[[Page 55550]]

additional option, to list for a limited period of time certain 
substances in the foamblowing sector, extruded polystyrene: Boardstock 
and billet end-use, as acceptable, subject to narrowed use limits. This 
proposal supplements the Agency's June 12, 2020, proposal with respect 
to the proposed listings in the foam-blowing sector, taking into 
consideration public comments and information received since issuance 
of the initial proposal. In the June 12, 2020, proposal, EPA proposed 
to list three foam blowing agent blends as acceptable. In this 
supplemental proposal, EPA is proposing an additional approach to list 
these blends as acceptable, subject to narrowed use limits, in the foam 
blowing sector, extruded polystyrene: Boardstock and billet end-use, 
from the effective date of a final rule based on this supplemental 
proposal until January 1, 2023. The Agency is providing an opportunity 
for public comment on this additional approach for the listings in the 
foam blowing sector, as well as reopening the public comment period for 
the proposed listings in the foam blowing sector in the June 12, 2020, 
proposal. The Agency is not reopening for comment those other portions 
of the June 12, 2020, proposal which are addressed in a separate final 
rule issued May 6, 2021.

DATES: Comments on this supplemental proposal must be received on or 
before November 22, 2021. Any party requesting a public hearing must 
notify the contact listed below under FOR FURTHER INFORMATION CONTACT 
by 5 p.m. Eastern Daylight Time on October 12, 2021. If a virtual 
hearing is held, it will take place on or before October 21, 2021 and 
further information will be provided on EPA's Stratospheric Ozone 
website at www.epa.gov/snap.

ADDRESSES: You may send comments, identified by docket identification 
(ID) number EPA-HQ-OAR-2019-0698, to the Federal eRulemaking Portal: 
http://www.regulations.gov. Follow the online instructions for 
submitting comments. Once submitted, comments cannot be edited or 
withdrawn. EPA may publish any comment received to its public docket. 
Do not submit electronically 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. 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, EPA's full 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. The EPA is temporarily suspending its Docket 
Center and Reading Room for public visitors, with limited exceptions, 
to reduce the risk of transmitting COVID-19. Our Docket Center staff 
will continue to provide remote customer service via email, phone, and 
webform. We encourage the public to submit comments via https://www.regulations.gov or email, as there may be a delay in processing 
mail and faxes. 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: Christina Thompson, Stratospheric 
Protection Division, Office of Atmospheric Programs (Mail Code 6205T), 
Environmental Protection Agency, 1200 Pennsylvania Ave. NW, Washington, 
DC 20460; telephone number: 202-564-0983; email address: 
thompson.christina@epa.gov. Notices and rulemakings under EPA's 
Significant New Alternatives Policy program are available on EPA's 
Stratospheric Ozone website at https://www.epa.gov/snap/snap-regulations.

SUPPLEMENTARY INFORMATION:

Table of Contents

I. General information
    A. Executive Summary and Background
    B. Does this action apply to me?
    C. What acronyms and abbreviations are used in the preamble?
II. What did EPA propose in the 2020 NPRM, including for extruded 
polystyrene: boardstock and billet?
III. What public comments and publicly available information has EPA 
included in the docket with respect to the proposed XPS listings 
since issuing the 2020 NPRM?
    A. Public Comments
    B. Additional Information
IV. What is EPA proposing in this supplemental proposal?
    A. Listing of Three Blends of HFC-134a as Acceptable, Subject to 
Narrowed Use Limits
    B. What are the three proposed HFC-134a blends and how do they 
compare to other foam blowing agents in the same end-use?
    C. Status of Specific HFC Blends
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
    C. Regulatory Flexibility Act
    D. Unfunded Mandates Reform Act
    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 That Significantly Affect 
Energy Supply, Distribution, or Use
    I. National Technology Transfer and Advancement Act
    J. Executive Order 12898: Federal Actions To Address 
Environmental Justice in Minority Populations and Low-Income 
Population
VI. References

I. General Information

A. Executive Summary and Background

    Pursuant to the Significant New Alternatives Policy (SNAP) program, 
EPA is proposing to list three foam blowing agent blends as acceptable, 
subject to narrowed use limits, in the foam blowing sector, extruded 
polystyrene: Boardstock and billet end-use. This proposal supplements 
the Agency's June 12, 2020, Notice of Proposed Rulemaking (NPRM), 
hereafter referred to as the ``2020 NPRM'' (85 FR 35874), with respect 
to the proposal to list these blends as acceptable, taking into 
consideration public comments and information received since issuance 
of the initial proposal. In the 2020 NPRM, EPA proposed to list three 
foam blowing agent blends as acceptable. In this supplemental proposal, 
EPA is proposing an additional approach to list the following blends as 
acceptable, subject to narrowed use limits, for use in extruded 
polystyrene: Boardstock and billet (XPS):
     Blends of 40 to 52 percent hydrofluorocarbon (HFC)-134a 
and the remainder hydrofluoroolefin (HFO)-1234ze(E);
     Blends of 40 to 52 percent HFC-134a with 40 to 60 percent 
HFO-1234ze(E) and 10 to 20 percent each water and carbon dioxide 
(CO2); and
     Blends with maximum of 51 percent HFC-134a, 17 to 41 
percent HFC-152a, up to 20 percent CO2, and one to 13 
percent water.
    If the approach discussed in this supplemental proposal is 
finalized, all three blends would be acceptable subject to a narrowed 
use limit for use in XPS from the effective date of a final rule based 
on this supplemental proposal until January 1, 2023, where other 
alternatives are not technically feasible for reasons of performance or

[[Page 55551]]

safety. EPA is taking comment on the proposed listings as well as the 
specific narrowed use limits discussed in this supplemental proposal. 
The Agency is also reopening the public comment period on the proposed 
acceptable listings for the same three foam blowing blends in the 2020 
NPRM, in light of information that has become publicly available and 
included in the docket for this rulemaking after the comment period 
closed for that proposal.
    In addition to listings for XPS, the 2020 NPRM included proposed 
listings of refrigerants for use in certain refrigeration and air 
conditioning end-uses, as well as a proposal to remove Powdered Aerosol 
E from the list of fire suppression substitutes acceptable subject to 
use conditions in total flooding applications. EPA is not reopening the 
comment period for those other portions of the 2020 NPRM which were 
addressed in a separate final rule (May 6, 2021; 86 FR 24444). Rather, 
this supplemental proposal relates only to the XPS listings. EPA 
intends to respond to comments on the 2020 NPRM's proposed listings for 
XPS together with comments on this supplemental proposal in a future 
final rule.
    This supplemental proposal is not EPA's response to the Mexichem 
Fluor, Inc. v. EPA decision of the United States Court of Appeals for 
the District of Columbia Circuit (``the D.C. Circuit'').\1\ In this 
supplemental proposal, as in the 2020 NPRM, EPA refers to listings made 
in a final rule issued on July 20, 2015. See 80 FR 42870 (``2015 
Rule''). The 2015 Rule, among other things, changed the listings for 
certain HFCs and blends from acceptable to unacceptable in various end-
uses in the aerosols, refrigeration and air conditioning, and foam 
blowing sectors. After a challenge to the 2015 Rule, the D.C. Circuit 
issued a partial vacatur of the 2015 Rule ``to the extent it requires 
manufacturers to replace HFCs with a substitute substance'' \2\ and 
remanded the rule to EPA for further proceedings.\3\ The D.C. Circuit 
also upheld EPA's listing changes as being reasonable and not 
``arbitrary and capricious.'' \4\ EPA intends to respond to the D.C. 
Circuit's decision in a future action.
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    \1\ 866 F.3d 451 (D.C. Cir. 2017).
    \2\ 866 F.3d at 462.
    \3\ Later, the court issued a similar decision on portions of a 
similar final rule issued December 1, 2016. 81 FR 86778 (``2016 
Rule''). See Mexichem Fluor, Inc. v. EPA, Judgment, Case No. 17-1024 
(D.C. Cir. Apr. 5, 2019), 760 F. App'x 6 (Mem).
    \4\ Mexichem Fluor, 866 F.3d at 462-63.
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    The SNAP program implements section 612 of the Clean Air Act (CAA). 
Background on the SNAP program is provided in the 2020 NPRM.
    For additional information on the SNAP program, visit the SNAP 
portion of EPA's Ozone Layer Protection website at www.epa.gov/snap. 
Copies of the full lists of acceptable substitutes for ozone depleting 
substances (ODS) in all industrial sectors are available at 
www.epa.gov/snap/substitutes-sector. For more information on the 
Agency's process for administering the SNAP program or criteria for 
evaluation of substitutes, refer to the initial SNAP rulemaking 
published on March 18, 1994 (59 FR 13044), codified at 40 CFR part 82, 
subpart G. SNAP decisions and the appropriate Federal Register 
citations are found at www.epa.gov/snap/snap-regulations. Substitutes 
listed as unacceptable; acceptable, subject to narrowed use limits; or 
acceptable, subject to use conditions, are also listed in the 
appendices to 40 CFR part 82, subpart G.

B. Does this action apply to me?

    The following list identifies regulated entities that may be 
affected by this proposed rule and their respective North American 
Industrial Classification System (NAICS) codes:

     All Other Basic Organic Chemical Manufacturing (NAICS 
325199)
     Polystyrene Foam Product Manufacturing (NAICS 326140)

C. What acronyms and abbreviations are used in the preamble?

    Below is a list of acronyms and abbreviations used in the preamble 
of this document:

AIHA--American Industrial Hygiene Association
ASTM--American Society for Testing and Materials
CAA--Clean Air Act
CAS Reg. No.--Chemical Abstracts Service Registry Identification 
Number
CBI--Confidential Business Information
CFR--Code of Federal Regulations
CO2--Carbon Dioxide
ECCC--Environment and Climate Change Canada
EPA--United States Environmental Protection Agency
EPS--Expanded Polystyrene
EU--European Union
FR--Federal Register
FTOC--Rigid and Flexible Foams Technical Options Committee
GWP--Global Warming Potential
HF--Hydrofluoric acid
HFC--Hydrofluorocarbon
HFO--Hydrofluoroolefin
ICF--ICF International, Inc.
IPCC--Intergovernmental Panel on Climate Change
NAICS--North American Industrial Classification System
NFPA--National Fire Protection Association
NIOSH--National Institute for Occupational Safety and Health
NPRM--Notice of Proposed Rulemaking
NRC--National Research Council
ODP--Ozone Depletion Potential
ODS--Ozone Depleting Substances
OMB--United States Office of Management and Budget
OSHA--United States Occupational Safety and Health Administration
PEL--Permissible Exposure Limit
PIR--Polyisocyanurate
ppm--Parts Per Million
PRA--Paperwork Reduction Act
RFA--Regulatory Flexibility Act
SDS--Safety Data Sheet
SNAP--Significant New Alternatives Policy
STEL--Short-term Exposure Limit
UMRA--Unfunded Mandates Reform Act
UL--Underwriters Laboratories, Inc.
USGCRP--U.S. Global Change Research Program
VOC--Volatile Organic Compounds
WEEL--Workplace Environmental Exposure Limit
WMO--World Meteorological Organization
XPS--Extruded Polystyrene: Boardstock and Billet

II. What did EPA propose in the 2020 NPRM, including for extruded 
polystyrene: Boardstock and billet?

    In the 2015 Rule, EPA changed the status of HFC-134a for use in 
XPS, from ``acceptable'' to ``acceptable subject to narrowed use limits 
for military or space- and aeronautics-related applications'' and 
``unacceptable for all other uses as of January 1, 2021,'' and as 
``unacceptable for all uses as of January 1, 2022.'' In another final 
rule issued December 1, 2016 (81 FR 86778), among other things, EPA 
revised the change of status dates for XPS for space- and aeronautics-
related applications, such that they are ``acceptable subject to 
narrowed use limits from January 1, 2021, through December 31, 2024,'' 
and ``unacceptable as of January 1, 2025.'' The December 1, 2016 final 
rule also applied unacceptability determinations for foam blowing 
agents to closed cell foam products and products containing closed cell 
foam.
    In the 2020 NPRM, EPA proposed to list three blends containing HFC-
134a as acceptable blowing agents in XPS: Blends of 40 to 52 percent 
HFC-134a by weight and the remainder HFO-1234ze(E); blends of 40 to 52 
percent HFC-134a with 40 to 60 percent HFO-1234ze(E) and 10 to 20 
percent each water and CO2 by weight; and blends with 
maximum of 51 percent HFC-134a, 17 to 41 percent HFC-152a, up to 20 
percent CO2 and 1 to 13 percent water. EPA also proposed to 
revise the unacceptable listing for blends of certain HFCs in XPS for 
consistency with the proposed acceptable listings for those blends of 
HFC-134a. Redacted submissions and supporting

[[Page 55552]]

documentation for these blends are provided in the docket for this 
proposed rule (EPA-HQ-OAR-2019-0698) at https://www.regulations.gov.\5\ 
\6\ \7\
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    \5\ Supporting Documentation for SNAP Rule 23 Listing of Blends 
of 40 to 52 Percent HFC-134a by Weight and the Remainder HFO-
1234ze(E) in Extruded Polystyrene: Boardstock and Billet. Submission 
Received July 20, 2017. Docket ID EPA-HQ-OAR-2019-0698-0023.
    \6\ Supporting Documentation for SNAP Rule 23 Listing of Blends 
of 40 to 52 Percent HFC-134a with 40 to 60 Percent HFO-1234ze(E) and 
10 to 20 Percent Each Water and CO2 by Weight in Extruded 
Polystyrene: Boardstock and Billet. Submission Received September 
24, 2018. Docket ID EPA-HQ-OAR-2019-0698-0024.
    \7\ Supporting Documentation for SNAP Rule 23 Listing of Blends 
with Maximum of 51 Percent HFC-134a, 17 to 41 Percent HFC-152a, up 
to 20 Percent CO2 and One to 13 Percent Water in Extruded 
Polystyrene: Boardstock and Billet. Submission Received November 7, 
2019. Docket ID EPA-HQ-OAR-2019-0698-0025.
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    In the 2020 NPRM, EPA proposed to list those three specific blends 
of HFC-134a as acceptable in XPS, stating that ``[t]hese blends have 
higher [global warming potentials] GWPs and are otherwise comparable or 
lower in risk than other alternatives listed as acceptable; however, 
EPA is taking this action because the Agency believes that other 
acceptable alternatives are not generally available for most needs 
under this end-use.'' 85 FR 35888.
    EPA also stated in the 2020 NPRM that, in order for substitutes to 
be ``available'' in the XPS end-use, they must be capable of blowing 
foam that meets the technical needs of XPS products including density 
and ability to meet testing requirements of building codes and 
standards, such as for thermal efficiency, compressive strength, and 
flame and smoke generation (85 FR 35888). Further, EPA noted that the 
company that initially submitted the three blends to the SNAP program 
for review indicated their difficulty meeting requirements for 
insulation value (``R-value'') with neat \8\ acceptable blowing agents 
such as HFO-1234ze(E), HFC-152a, and CO2.\9\ The submitter 
indicated that if in some cases it could meet R-value requirements with 
those neat blowing agents, these alternatives were not able to meet 
other requirements such as compressive strength, density and thickness, 
or fire test results. The submitter also identified challenges with 
meeting code requirements for XPS products manufactured with flammable 
substitutes (e.g., HFC-152a, light saturated hydrocarbons C3-C6, and 
methyl formate) and provided examples of failed test results \10\ (85 
FR 35888).
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    \8\ Individual, unblended blowing agents.
    \9\ DuPont, 2019b. December 17, 2019 Letter from DuPont 
Performance Building Solutions to EPA. Docket ID EPA-HQ-OAR-2019-
0698-0008.
    \10\ DuPont, 2019b. Op. cit.
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    Based on the evidence before the Agency at the time of the 2020 
NPRM, EPA stated that it appeared that only one of the substitutes that 
the Agency believed at the time of the 2015 Rule would be available for 
use in XPS foam as of January 1, 2021, was in fact available, and that 
it likely could only be used to meet the needs for some portion of the 
XPS foams market.\11\ Based on concerns about ensuring that the needs 
of the full XPS foams market in the United States could be met and not 
limiting the choice of acceptable substitutes to only one option, EPA 
proposed to list additional blowing agent options for XPS that have 
been proven to work for this end-use.
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    \11\ In the 2020 NPRM, EPA further stated that the set of 
products that may be able to be manufactured with that substitute, 
HFC-152a, would account for a minority of the current market for XPS 
(85 FR 35888, footnote 54). As discussed further below, the 
statement that HFC-152a was being used alone may have been a 
misunderstanding.
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    In the 2020 NPRM, EPA also proposed to revise the current 
unacceptable listing for blends of certain HFCs in XPS in appendix U to 
40 CFR part 82, subpart G. The listing for unacceptable substitutes in 
XPS states that HFC-134a, HFC-245fa, HFC-365mfc, and blends thereof; 
and Formacel TI, Formacel B, and Formacel Z-6 are ``unacceptable as of 
January 1, 2021, except where allowed under a narrowed use limit.'' For 
consistency with the proposed acceptable listings, EPA proposed to 
revise this listing of unacceptable substitutes for XPS in appendix U 
to read that the substitutes are ``Unacceptable as of January 1, 2021 
except where allowed under a narrowed use limit or where blends are 
specifically listed as acceptable.'' The 2020 NPRM further stated that 
EPA was not opening up for comment other aspects of the existing 
listing (85 FR 35889).
    The 2020 NPRM also included proposals that are not affected by this 
supplemental proposal. Those were proposals for listing three 
refrigerants as acceptable, subject to narrowed use limits, for use in 
retail food refrigeration--medium-temperature stand-alone units for new 
equipment and for listing six refrigerants as acceptable, subject to 
use conditions, in certain types of new equipment for residential and 
light commercial air conditioning and heat pumps, as well as a proposal 
to remove Powdered Aerosol E from the list of fire suppression 
substitutes that are ``acceptable subject to use conditions'' in total 
flooding applications (85 FR 35874-75). The comment period for those 
portions of the proposal ended on July 27, 2020. This supplemental 
proposal does not reopen the comment period for those portions of the 
2020 NPRM which were addressed in a separate final rule issued on May 
6, 2021 (86 FR 24444).

III. What public comments and publicly available information has EPA 
included in the docket with respect to the proposed XPS listings since 
issuing the 2020 NPRM?

    During the public comment period for the 2020 NPRM, EPA received 
comments with respect to the proposal to list three blends containing 
HFC-134a as acceptable blowing agents in XPS. EPA also received and 
found information related to the role of codes and standards for 
residential insulation and the availability of alternative foam blowing 
agents. These comments and additional information supplement the 
information available to the Agency at the time of the 2020 NPRM and 
are available in the public docket.

A. Public Comments

    In this section of the preamble, EPA is summarizing certain 
relevant public comments that shared new information or suggested 
different approaches to listing the three proposed blends. EPA also 
received other public comments related to the proposed listings in the 
2020 NPRM for three blends of HFC-134a for XPS that are not summarized 
below. The Agency intends to address all comments on the 2020 NPRM and 
on this supplemental proposal in any subsequent final rule.
    Most of the public comments on foam blowing agents for XPS in the 
2020 NPRM opposed listing the proposed blends as acceptable, while two 
manufacturers of XPS supported the proposed acceptable listings. 
Opposing commenters stated that there are other alternatives 
commercially available with lower GWP for use in XPS boardstock that 
are currently being used in other countries, such as Japan, Saudi 
Arabia, Canada, and member nations of the European Union (EU); and 
those commenters provided links to further information. Those 
commenters included one manufacturer of XPS, manufacturers of competing 
types of foam insulation (e.g., polyisocyanurate [PIR] laminated 
boardstock, expanded polystyrene [EPS]) and their trade organizations, 
blowing agent producers, and environmental organizations. Two 
environmental organizations provided information on recent research 
into the use of CO2 as a blowing agent for XPS. Some of the 
commenters also requested that EPA list additional blowing agents for 
XPS that were under the SNAP program's review at the time of the 2020

[[Page 55553]]

NPRM. In contrast, the submitter of the three proposed blends commented 
that because of differences in XPS manufacturing and code requirements 
across jurisdictions, comparing XPS blowing agents between the U.S., 
Canada, and the EU is not appropriate. That commenter stated that they 
had patented low-GWP blends for the Japanese market, but that those 
blends could not meet the stricter fire codes in the North American 
market. A different U.S. XPS manufacturer commented that they had been 
using Formacel Z-6, a blend of HFC-152a, HFC-134a, and HFC-134, and 
requested that EPA, if listing the three proposed blends as acceptable 
in its final rule, clarify that the version of the Formacel Z-6 blend 
used in the commenter's products is acceptable; at the time of the 2020 
NPRM, EPA had incorrectly understood that this company was using neat 
HFC-152a as their blowing agent.\12\
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    \12\ This misunderstanding was the basis for the Agency's 
statements in the 2020 NPRM that ``one of the three manufacturers of 
XPS in the United States has had some success using neat HFC-152a as 
a blowing agent to manufacture some XPS products'' and ``only one of 
the substitutes that the Agency believed at the time of the 2015 
Rule would be available for use in XPS foam as of January 1, 2021 is 
in fact available and likely could only be used to meet the needs 
for some portion of the XPS foams market.'' 85 FR at 35888. 
Subsequent to the 2020 NPRM, EPA has learned from public comments 
that, in fact, no U.S. XPS manufacturers are using neat HFC-152a.
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    Some commenters mentioned that certain states have adopted 
regulations that control HFCs.\13\ The submitter of the proposed blends 
specifically mentioned timelines imposed by state regulations 
prohibiting certain blowing agents in XPS as a reason why they needed 
to use the proposed blends. An environmental group also noted in its 
comments that to be ``fully compliant with the various state adoptions 
of the Significant New Alternatives Policy (SNAP) Program in the United 
States and Canadian Environmental Protection Act in Canada,'' as the 
submitter claims, the submitter would need to use already-approved 
substances.\14\ Another manufacturer of XPS commented that the majority 
of the state laws that prohibit HFC-134a in XPS contemplate further 
regulatory action ``to conform'' state law to any federal SNAP 
requirement that approves a previously prohibited HFC blend for foam 
blowing. This commenter expressed concern that EPA's decisions in the 
rule could flow through to state law and that there could be 
inappropriate environmental and potentially anticompetitive impacts if 
EPA were to reach a conclusion (i.e., finalize the proposed listings 
for the three blends in the 2020 NPRM) without knowledge of all U.S. 
products available in the market.
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    \13\ To provide additional context, EPA notes that several 
states have taken action to restrict the use of certain HFCs as foam 
blowing agents for XPS that would prohibit use of HFC-134a or blends 
thereof. To date, twelve of those states have issued final rules: 
California, Colorado, Delaware, Maine, Maryland, Massachusetts, New 
Jersey, New York, Rhode Island, Vermont, Virginia, and Washington. 
Maine, Rhode Island, Vermont and Virginia have established a 
compliance deadline of January 1, 2022; Delaware has a compliance 
deadline of September 1, 2021; Maryland has a compliance deadline of 
July 1, 2021; and the remaining six states have a compliance 
deadline of January 1, 2021.
    \14\ EPA is aware of Canadian regulations (the Ozone-Depleting 
Substances and Halocarbon Alternatives Regulations) which as of 
January 1, 2021, prohibit the import and the manufacture of a 
plastic foam or a rigid foam product in which a listed HFC 
(including HFC-134a) is used as a foaming agent (i.e., blowing 
agent) if the GWP of the foaming agent is greater than 150. 
(Additional information is available about these regulations online 
at https://pollution-waste.canada.ca/environmental-protection-registry/regulations/view?Id=129.) The regulations include 
provisions to issue essential purpose permits that would allow for 
the manufacture or import of a foam product if the product will be 
used for an essential purpose and if a permit is specifically issued 
under the regulations for that purpose. Environment and Climate 
Change Canada (ECCC) issued essential purpose permits for the import 
and/or manufacture of three companies' brands of extruded 
polystyrene foam insulation boardstock with a foaming agent 
containing HFCs and with a GWP below specified value. One of these 
was an essential purpose permit expiring on December 31, 2022 for 
XPS using a foam blowing agent containing HFCs and with a GWP of 750 
or less manufactured by DuPont; this description corresponds with 
the blends proposed in the 2020 NPRM and in this supplemental 
proposal for XPS. ECCC also issued essential purpose permits 
expiring on December 31, 2021 for XPS manufactured by Owens Corning 
and by Kingspan Insulation. The information pertaining to essential 
purpose permits issued by ECCC is available online at: https://www.canada.ca/en/environment-climate-change/services/canadian-environmental-protection-act-registry/permits/authorizations-ozone-depleting-substances.html.
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    Commenters disagree as to whether flammability of substitutes 
currently listed as acceptable was of concern. Some commenters 
commented that flammability risks of blowing agents already listed as 
acceptable, and particularly of HFO-1234ze(E), were not significantly 
different from flammability risks for HFC-134a. In contrast, the 
original submitter of the proposed blends commented that during use of 
HFO-1234ze(E) without HFC-134a, they had ``industrial hygiene'' events 
where excessive hydrofluoric acid (HF) was generated due to 
decomposition of the blowing agent under heat and more cases of 
``unplanned combustion''; they reported that these problems were 
resolved when using HFC-134a in the blend.
    Multiple commenters representing manufacturers of EPS or of PIR 
foam insulation questioned statements in the preamble to the 2020 NPRM 
concerning codes and standards and how they relate to having sufficient 
options for the XPS end-use. For example, representatives of the EPS 
industry commented that the specifications of American Society for 
Testing and Materials (ASTM) Standard C578 are only required by 
building codes in certain situations, such as use above-grade. 
Commenters from the EPS industry stated that XPS products could still 
be sold as a different type classification of insulation under the ASTM 
C578 standard if they failed to meet the specifications for the type 
classifications for which XPS typically is used (e.g., multiple types 
requiring an R-value of at least 5 per inch). Manufacturers of XPS foam 
responded to such comments in a presentation given to EPA,\15\ stating 
that a change to a different type classification would impact their 
ability to fill their customer's specific application needs and 
reductions in R-value force an increase in product thicknesses to 
comply with building energy codes. A commenter from the EPS industry 
stated that there are a variety of flammability-related tests for 
insulation foam, including both testing for flame and smoke generation 
that is required by building codes (ASTM E84 or Underwriters 
Laboratories [UL] 723) and others ``for which alternative solutions 
exist in the code if the product fails these tests, such as FM [Factory 
Mutual] 4880, NFPA [National Fire Protection Association] 286, UL 1715, 
etc.''
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    \15\ DuPont, 2020a. August 23, 2020. DuPont Performance Building 
Solutions. SNAP Rule 23 Discussion with EPA.
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    One commenter suggested that a sunset date be included for any 
``Acceptable'' formulations that include high-GWP chemicals. This 
commenter stated that that they recognize that change takes time and 
suggested that the blends proposed in the 2020 NPRM provide a phased 
approach to eventually eliminate high-GWP HFC foaming agents from XPS 
products in the United States. The commenter also suggested that if the 
EPA decides the three proposed blends should be added to the 
``Acceptable'' list, the corresponding ``Unacceptable'' list should be 
updated to include a deadline for these formulas and not be left open 
ended. The submitter of the three proposed blends also mentioned timing 
as a concern in their comments on the 2020 NPRM, stating non-flammable 
blowing agent blends are necessary because of state regulatory 
timelines for transition away from prohibited components of blowing 
agents in XPS in some cases as early as January 1, 2021.

[[Page 55554]]

That commenter stated that products that meet qualification testing 
with flammable blowing agents require longer development lead times. 
The submitter of the three proposed blends subsequently sent EPA a late 
comment, noting the other comment concerning a sunset date or deadline 
for the proposed blends and stating that they would support the 
inclusion of a two-year deadline for the blends in the final rule, 
where the blends would no longer be ``acceptable'' after the deadline. 
In this late comment, the submitter of the three proposed blends said 
``[i]ncluding a deadline in the final rule could alleviate many of the 
concerns raised by commenters, as a deadline would significantly limit 
the scope of any alleged impacts of the rule.'' They also stated that 
they are ``committed and actively working to find solutions with 
further reduced [GWP],'' and that they ``view the SNAP Rule 23 blends 
as a critical, but not permanent, step in [their] GWP phasedown plan.'' 
\16\ The EPA will address all comments received regarding these three 
blends in the XPS end-use on the 2020 NPRM and on this supplemental 
proposal in considering any final action on them.
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    \16\ DuPont, 2020b. November 20, 2020 Letter from J. Hansbro, 
DuPont Performance Building Solutions, to C. Grundler and C. 
Newberg, EPA. Available in docket EPA-HQ-OAR-2019-0698.
---------------------------------------------------------------------------

B. Additional Information

    The Agency has obtained additional information since issuance of 
the 2020 NPRM. Some of this is information provided by commenters, such 
as the names and websites of XPS manufacturers in Europe and Asia using 
low-GWP blowing agents and a link to a report, ``Final Scientific 
Report for DOE/EERE, A New Generation of Building Insulation by Foaming 
Polymer Blend Materials with CO2'' (Industrial Science & 
Technology Network, Inc. 2016).\17\ The information on the XPS 
manufacturers in Europe and Asia indicates that a number of XPS 
manufacturers globally are using foam-blowing agents that comply with 
regulations restricting their GWP to 150 or less; however, there is not 
corresponding information indicating that the same industry standards 
or code requirements apply in these countries as in the United States. 
The DOE/EERE report concerns an experimental technology for using 
CO2 in XPS with improved thermal insulation values. The 
report indicates that the technology is not yet commercially available. 
EPA also has learned that the company Soprema, which manufactures XPS 
in Europe using CO2, now operates a facility in Canada that 
uses a blowing agent with a GWP less than 50 to manufacture XPS.\18\
---------------------------------------------------------------------------

    \17\ This report is in the docket for this rulemaking, EPA-HQ-
OAR-2019-0986, and is available online at https://www.osti.gov/servlets/purl/1244652.
    \18\ https://blog.soprema.ca/en/whats-new-with-sopra-xps.
---------------------------------------------------------------------------

    Other publicly available information included in the docket for 
this rulemaking after the 2020 NPRM includes the 2018 report of the 
Rigid and Flexible Foams Technical Options Committee (FTOC 2018). FTOC 
2018 states that some reasons why CO2 could not be adopted 
universally as a blowing agent include the following:
     Processing difficulties with CO2 and even 
CO2/oxygenated hydrocarbon or CO2/hydrocarbon 
blends;
     The higher gaseous thermal conductivity leading to poorer 
thermal efficiency of the foam;
     Costs of conversion--including licensing constraints 
resulting from patents; and
     Loss of processing flexibility ruling out some board 
geometries completely. FTOC 2018 also states,

    CO2-based blends are now dominant in the European 
extruded polystyrene (XPS) industry either alone or blended with 
other blowing agents. . . . In North America where the lower lambda 
[i.e., with higher thermal resistance and energy efficiency] product 
is required, HFCs still dominate. By contrast, much of the European 
XPS market is targeted at requirements, such as floor insulation, 
where its moisture resistance is particularly valuable. In these 
applications, board geometries are less critical.

In addition, since issuance of the 2020 NPRM, EPA has continued our 
review of submissions for new substitutes for use in XPS. On December 
11, 2020, the Agency listed blends of 10 to 99 percent by weight HFO-
1336mzz(Z) and the remainder HFC-152a as acceptable for use in XPS (85 
FR 79863). Those blends have an ozone depletion potential (ODP) of 
zero, range in GWP from about three to 110, contain chemicals that are 
excluded from the definition of volatile organic compounds (VOC), are 
flammable depending on the specific composition of the blend, and are 
able to be used consistent with the workplace environmental exposure 
limits (WEELs) for HFC-152a and for HFO-1336mzz(Z). For more detailed 
information on the human health and environmental effects of these 
blends, see ``Protection of Stratospheric Ozone: Determination 36 for 
Significant New Alternatives Policy Program'' (85 FR 79863) and public 
docket EPA-HQ-OAR-2003-0118 at www.regulations.gov. In addition, since 
issuance of the 2020 NPRM, EPA's SNAP program has received and is 
continuing its technical review of additional submissions of foam 
blowing agents for use in XPS.

IV. What is EPA proposing in this supplemental proposal?

    Taking into consideration the information discussed in the 2020 
NPRM, the public comments received on the 2020 NPRM and information 
available to EPA since issuance of that initial proposal, EPA is 
proposing to list the following three blends of HFC-134a as 
``acceptable, subject to narrowed use limits,'' in XPS from the 
effective date of a final rule based on this supplemental proposal 
until January 1, 2023:
     Blends of 40 to 52 percent HFC-134a and the remainder HFO-
1234ze(E);
     Blends of 40 to 52 percent HFC-134a with 40 to 60 percent 
HFO-1234ze(E) and 10 to 20 percent each water and CO2; and
     Blends with maximum of 51 percent HFC-134a, 17 to 41 
percent HFC-152a, up to 20 percent CO2 and one to 13 percent 
water.
    These are the same three blowing agent blends of HFC-134a that EPA 
proposed to list as ``acceptable'' in the 2020 NPRM. Through this 
supplemental proposal, EPA is offering an opportunity for comment on 
modifications to the listings for these three blends proposed in the 
2020 NPRM as well as the specific narrowed use limits. As noted above, 
in light of information that has become publicly available and included 
in the docket after the comment period closed for the 2020 NPRM, we are 
also reopening the public comment period on the proposed listings in 
the 2020 NPRM for these same three blends--i.e., listing the three 
proposed blends as ``acceptable'' and changing the unacceptability 
listing for HFC blends in XPS to allow for specific ``acceptable'' 
listings. You may find the proposed regulatory text at the end of this 
document.

A. Listing of Three Blends of HFC-134a as Acceptable, Subject to 
Narrowed Use Limits

    Under SNAP, listings of substitutes as ``acceptable, subject to 
narrowed use limits,'' permit a narrowed range of use of a substitute 
within an end-use or sector. As described in the 1994 SNAP Framework 
Rule (Mar. 18, 1994) (59 FR 13044 at 13051), where EPA narrows uses, a 
substitute will be acceptable for use only in certain applications 
under SNAP, as where other alternatives are not technically feasible 
due to performance or safety requirements. Thus, narrowed use limits 
define in

[[Page 55555]]

which end-uses and applications an otherwise unacceptable substitute 
may be used under SNAP.
    In this supplemental proposal, EPA is proposing to list the three 
HFC-134a blends as ``acceptable, subject to narrowed use limits,'' 
because publicly available information that EPA has included in the 
docket supports consideration of this additional option as an 
alternative to the proposal to list them as ``acceptable'' without 
restriction in the 2020 NPRM. This information indicates that a new 
blowing agent is potentially available and others are likely to be 
available in the future that would result in overall risk to human 
health and the environment comparable to currently acceptable 
substitutes and lower than the overall risks of the proposed blends. 
Since issuance of the 2020 NPRM, EPA has listed another blowing agent 
as acceptable for use in XPS: Blends of 10 to 99 percent by weight HFO-
1336mzz(Z) and the remainder HFC-152a. In addition, as commenters have 
noted, other blowing agents such as HFO-1234ze(E) and CO2 
are being used successfully for manufacturing XPS in other countries 
where there are requirements to use blowing agents with a GWP less than 
150. Accordingly, EPA is proposing to include a narrowed use limit in 
the listing that would allow use under SNAP of the proposed blends in 
XPS from the effective date of a final rule based on this supplemental 
proposal until January 1, 2023, where other alternatives are not 
technically feasible for reasons of performance or safety. At the same 
time, EPA is proposing to list the three blends of HFC-134a as 
acceptable, subject to narrowed use limits, because we understand that 
U.S. XPS manufacturers are in the process of transitioning to other 
lower GWP blowing agents, and we understand that additional technical 
work is needed. For example, if an XPS manufacturer has not been using 
highly or moderately flammable blowing agents in the past, it will 
require additional time to test and adjust engineering controls to 
address the higher degree of flammability and the greater amount of HF 
that would be generated with the more flammable blowing agents. In 
addition, even with non-flammable blowing agents such as 
CO2, additional time would be required to test and, if 
necessary, to adjust formulations or manufacturing processes, in order 
to meet performance requirements. Based on a late comment from one XPS 
manufacturer, we expect that it will take no more than two years from 
the original change of status date of January 1, 2021, for that work to 
be complete, such that these other blowing agents will be available and 
can meet the needs met by current XPS products.
    EPA is proposing that the three proposed blends would be acceptable 
from the effective date of the final rule associated with this 
supplemental notice of proposed rulemaking--which we anticipate would 
be 30 days after publication of a final rule in the Federal Register--
until January 1, 2023, to allow a limited time for fine-tuning of new 
formulations currently in development. This timing would also be 
consistent with a time period suggested in a late comment from the 
submitter of the three blends. We note that we may issue a final rule 
with a different time period e.g., 18 or 36 months after January 1, 
2021, for example, if comments and information submitted during the 
public comment period on this supplemental proposal indicate that a 
different time period would be reasonable.
    The existing SNAP rules pertaining to narrowed use limits provide 
that users intending to adopt a substitute ``acceptable with narrowed 
use limits'' must ascertain that other alternatives are not technically 
feasible and document the results of their evaluation that showed the 
other alternatives to be not technically feasible and maintain that 
documentation in their files. 40 CFR 82.180(b)(3). This documentation, 
which does not need to be submitted to EPA unless requested to 
demonstrate compliance, ``shall include descriptions of substitutes 
examined and rejected, processes or products in which the substitute is 
needed, reason for rejection of other alternatives, e.g., performance, 
technical or safety standards, and the anticipated date other 
substitutes will be available and projected time for switching to other 
available substitutes.'' 40 CFR 82.180(b)(3).
    EPA is also reopening comment on the proposed ``acceptable'' 
listings for these three blends of HFC-134a from the 2020 NPRM, in 
light of information that has become publicly available and included in 
the public docket after the comment period closed for that proposal, 
including the listing of another blowing agent as acceptable for use in 
XPS (blends of 10 to 99 percent by weight HFO-1336mzz(Z) and the 
remainder HFC-152a).\19\ Further, EPA requests comment on whether there 
are likely to be adequate options available by January 1, 2023, that 
would reduce overall risks to human health and the environment, and 
whether those options would prove to be technically feasible and 
sufficient in supply by that date to serve the full needs of the XPS 
foam market. If, taking all the relevant and available information into 
account, EPA were to conclude that there would not be adequate options, 
or that the options would not prove to be technically feasible or 
sufficient in supply, an acceptable, unrestricted listing without a 
sunset date, as proposed in the 2020 NPRM, might be more appropriate 
than a listing as ``acceptable subject to narrowed use limits'' or an 
``acceptable'' listing with a sunset date.
---------------------------------------------------------------------------

    \19\ In this regard, EPA notes that section IV.B of this 
supplemental proposal discusses the three proposed HFC-134a blends 
and how they compare to other foam blowing agents in the same end-
use, including the most recently listed acceptable alternative.
---------------------------------------------------------------------------

    In the 2015 Rule, EPA changed the status of certain HFCs and HFC 
blends from ``acceptable'' to ``unacceptable'' in XPS as of January 1, 
2021, including HFC-134a, HFC-245fa, HFC-365mfc, and blends 
thereof.\20\ Recognizing that multiple steps needed to be taken to 
transition to other blowing agents, including research and testing, EPA 
provided several years for those actions prior to the change of status 
date of January 1, 2021. The Agency now anticipates that sufficient 
alternatives will be available and technically feasible for XPS by 
January 1, 2023. Thus, EPA is proposing to list additional blowing 
agent options for XPS that have been proven to work for this end-use on 
a limited basis by listing them as ``acceptable, subject to narrowed 
use limits'' from the effective date of a final rule based on this 
supplemental proposal until January 1, 2023.
---------------------------------------------------------------------------

    \20\ As noted above, the D.C. Circuit partially vacated and 
remanded the 2015 Rule while also upholding EPA's listing changes as 
being reasonable and not ``arbitrary and capricious.'' Mexichem 
Fluor, 866 F.3d at 462-63. This supplemental proposal is not EPA's 
response to the court's decision.
---------------------------------------------------------------------------

    EPA is taking comment on the proposed listings as well as the 
specific narrowed use limits discussed above. In particular, EPA 
requests comment on the appropriate time period for listing the blends 
as ``acceptable, subject to narrowed use limits.'' We also request 
comment on whether January 1, 2023, is a reasonable date or whether, as 
noted above, the Agency should consider an earlier or later date in the 
range of July 1, 2022 to January 1, 2024, and why. In addition, EPA is 
considering whether there are other possible approaches to issuing a 
time-limited acceptable listing for these three blends for use in the 
XPS end-use, such as adding an ``acceptable'' listing with a sunset 
date in the same range to the SNAP listings in 40 CFR part 82, subpart 
G (e.g., listing as ``acceptable from the effective date of the final 
rule to January 1, 2023''). This

[[Page 55556]]

alternative approach would have the effect of listing these three 
blends as acceptable for a similar, limited time as for the proposal to 
list the blends as ``acceptable, subject to narrowed use limits,'' but 
the time limitation would not be expressed as a narrowed use limit. 
Under this alternative approach, the user would not need to ascertain 
further that other alternatives are not technically feasible, document 
the results of their evaluation that showed the other alternatives to 
be not technically feasible, or maintain that documentation in their 
files, unlike with narrowed use limits.\21\ EPA solicits comments on 
this alternative approach.
---------------------------------------------------------------------------

    \21\ I.e., under the alternative approach, it would not be 
necessary to meet the requirements of 40 CFR 82.180(b)(3).
---------------------------------------------------------------------------

B. What are the three proposed HFC-134a blends and how do they compare 
to other foam blowing agents in the same end-use?

    EPA notes that the information in this section is similar to that 
provided in the 2020 NPRM (85 FR at 35887), but is updated to reflect 
the most recent listing of acceptable substitutes for XPS (December 11, 
2020; 85 FR 79863). In addition, EPA has updated GWP values to use the 
100-year GWP from the Assessment of Ozone Depletion: 2018 (WMO, 2018) 
for certain compounds that did not have a GWP value published in the 
International Panel on Climate Change's Fourth Assessment Report (e.g., 
HFOs, methyl formate).
    EPA is proposing to list as ``acceptable subject to narrowed use 
limits'' (1) blends of 40 to 52 percent HFC-134a by weight and the 
remainder HFO-1234ze(E) for use in XPS (hereafter referred to as ``HFC-
134a/HFO-1234ze(E) blends''); (2) blends of 40 to 52 percent HFC-134a 
with 40 to 60 percent HFO-1234ze(E) and 10 to 20 percent each water and 
CO2 by weight for use in XPS (hereafter referred to as 
``CO2/water/HFC-134a/HFO-1234ze(E) blends''); and (3) blends 
with maximum of 51 percent HFC-134a, 17 to 41 percent HFC-152a, up to 
20 percent CO2 and 1 to 13 percent water (hereafter referred 
to as ``HFC-134a/HFC-152a/CO2/water blends''). The 
components of the blends are co-blown and component percentages are by 
weight.
    HFC-134a is also known as 1,1,1,2-tetrafluoroethane (CAS Reg. No. 
811-97-2). HFC-152a, also known as 1,1, difluoroethane, has CAS Reg. 
No. 75-37-6. HFO-1234ze is also known as HFC-1234ze, HFO-1234ze(E) or 
trans-1,3,3,3-tetrafluoroprop-1-ene (CAS Reg. No. 29118-24-9). 
CO2 has CAS Reg. No. 124-38-9, and water has CAS Reg. No. 
7732-18-5.
    Redacted submissions and supporting documentation for these blends 
are provided in the docket related to this supplemental proposal (EPA-
HQ-OAR-2019-0698) at https://www.regulations.gov. EPA performed 
assessments to examine the health and environmental risks of these 
substitutes. These assessments are available in the docket related to 
this supplemental proposal.22 23 24
---------------------------------------------------------------------------

    \22\ ICF, 2020a. Risk Screen on Substitutes in Extruded 
Polystyrene Boardstock and Billet Foam; Substitute: Blends of 40 to 
52 Percent HFC-134a by Weight and the Remainder HFO-1234ze(E) (HFC-
HFO Co-blowing Agents).
    \23\ ICF, 2020b. Risk Screen on Substitutes in Extruded 
Polystyrene Boardstock and Billet Foam; Substitute: Blends of 40 to 
52 Percent HFC-134a with 40 to 60 Percent HFO-1234ze(E) and 10 to 20 
Percent Each Water and CO2 by Weight (Co-blowing Blends).
    \24\ ICF, 2020c. Risk Screen on Substitutes in Extruded 
Polystyrene Boardstock and Billet Foam; Substitute: Blends with 
Maximum of 51 Percent HFC-134a, 17 to 41 Percent HFC-152a, up to 20 
Percent CO2 and One to 13 Percent Water (Blends for Foam 
Blowing).
---------------------------------------------------------------------------

    Environmental information: The substitutes have ODPs of zero. Their 
components, HFC-134a, HFC-152a, HFO-1234ze(E), CO2, and 
water have GWPs of 1,430,\25\ 124,\26\ one,\27\ one,\28\ and less than 
one,\29\ respectively. If these values are weighted by mass percentage, 
then the blends range in GWP from about 580 to 750.\30\ HFC-134a, HFC-
152a, HFO-1234ze(E), CO2, and water--components of the 
blends--are excluded from EPA's regulatory definition of VOC under CAA 
regulations that address the development of state implementation plans 
to attain and maintain the National Ambient Air Quality Standards. See 
40 CFR 51.100(s).
---------------------------------------------------------------------------

    \25\ IPCC, 2007. Climate Change 2007: The Physical Science 
Basis. Contribution of Working Group I to the Fourth Assessment 
Report of the Intergovernmental Panel on Climate Change. Solomon, 
S., Qin, D., Manning, M., Chen, Z., Marquis, M., Averyt, K.B., 
Tignor, M., and Miller, H.L. (eds.). Cambridge University Press. 
Cambridge, United Kingdom and New York, NY, USA. Available online 
at: www.ipcc.ch/publications_and_data/ar4/wg1/en/contents.html.
    \26\ IPCC, 2007.
    \27\ WMO (World Meteorological Organization), Scientific 
Assessment of Ozone Depletion: 2018, Global Ozone Research and 
Monitoring Project--Report No. 58, 588 pp., Geneva, Switzerland, 
2018. Available at: https://ozone.unep.org/sites/default/files/2019-05/SAP-2018-Assessment-report.pdf. In this action, the 100-year GWP 
values are used.
    \28\ IPCC, 2007.
    \29\ Sherwood et al 2018. This paper estimated that water vapor 
emitted near Earth's surface due to anthropogenic sources (e.g. 
irrigation) would have a GWP of -10-3 to 5 x 
10-4. ``The global warming potential of near-surface 
emitted water vapour,'' Steven C Sherwood, Vishal Dixit and 
Chrys[eacute]is Salomez. Environ. Res. Lett. 13 (2018) 104006.
    \30\ A GWP of 580 corresponds to formulations containing 
approximately 40 percent HFC-134a and the remainder either HFO-
1234ze(E); HFO-1234ze(E), CO2, and water; or HFC-152a, 
CO2, and water. A GWP of 750 corresponds to formulations 
containing 52 percent HFC-134a and the remainder either HFO-
1234ze(E); HFO-1234ze(E), CO2, and water; or 
alternatively containing 51 percent HFC-134a and the remainder HFC-
152a, CO2, and water.
---------------------------------------------------------------------------

    Flammability information: The component HFC-152a is moderately 
flammable. The other components of the blends are non-flammable at 
standard temperature and pressure using the standard test method ASTM 
E681. However, at higher temperatures, such as the temperatures typical 
for extruding XPS, HFC-134a and HFO-1234ze(E) may be flammable, 
particularly at higher humidity levels.\31\ The XPS manufacturer 
submitting the blends has found that blends containing 50 percent or 
more HFC-134a have acceptable flammable process stability under 
conditions of use (i.e., XPS extrusion).\32\
---------------------------------------------------------------------------

    \31\ Bellair and Hood, 2019. Comprehensive evaluation of the 
flammability and ignitability of HFO-1234ze, R.J. Bellair and L. 
Hood, Process Safety and Environmental Protection 132 (2019) 273-
284. Available online at doi.org/10.1016/j.psep.2019.09.033.
    \32\ DuPont, 2019a. August 23, 2019. Letter from DuPont 
Performance Building Solutions to EPA. Docket ID EPA-HQ-OAR-2019-
0698-0007.
---------------------------------------------------------------------------

    Toxicity and exposure data: Potential health effects of these 
substitutes at lower concentrations include headache, nausea, 
drowsiness, and dizziness. The substitutes may also irritate the skin 
or eyes or cause frostbite. At sufficiently high concentrations, they 
may cause central nervous system depression and affect respiration. The 
substitutes could cause asphyxiation, if air is displaced by vapors in 
a confined space. These health effects are common to many foam blowing 
agents.
    The American Industrial Hygiene Association (AIHA) has established 
WEELs of 1,000 ppm as an eight-hour time-weighted average for HFC-134a 
and HFC-152a and 800 ppm for HFO-1234ze(E). CO2 has an eight 
hour/day, 40 hour/week permissible exposure limit (PEL) of 5000 ppm in 
the workplace required by the Occupational Safety and Health 
Administration (OSHA), and a 15-minute recommended short-term exposure 
limit (STEL) of 30,000 ppm established by the National Institute for 
Occupational Safety and Health (NIOSH). EPA anticipates that users will 
be able to meet the AIHA WEELs, OSHA PEL, and NIOSH STEL and address 
potential health risks by following requirements and recommendations in 
the manufacturer's safety data sheets (SDSs) and other safety 
precautions common to the foam blowing industry.
    Comparison to other substitutes in this end-use: HFC-134a/HFO-
1234ze(E)

[[Page 55557]]

blends, CO2/water/HFC-134a/HFO-1234ze(E) blends, and HFC-
134a/HFC-152a/CO2/water blends have ODPs of zero, comparable 
to all other acceptable substitutes in this end-use, such as blends of 
10 to 99 percent by weight HFO-1336mzz(Z) and the remainder HFC-152a 
\33\ (hereafter called ``HFO-1336mzz(Z)/HFC-152a blends''), HFC-152a, 
HFO-1234ze(E), methyl formate, and CO2.
---------------------------------------------------------------------------

    \33\ These blends range in composition from 10 percent HFO-
1336mzz(Z) and 90 percent HFC-152a to 99 percent HFO-1336mzz(Z) and 
1 percent HFC-152a.
---------------------------------------------------------------------------

    The GWPs of 580 to 750 for the HFC-134a/HFO-1234ze(E) blends, the 
CO2/water/HFC-134a/HFO-1234ze(E) blends, and HFC-134a/HFC-
152a/CO2/water blends are higher than those for acceptable 
alternatives such as HFC-152a, HFO-1234ze(E), HFO-1336mzz(Z)/HFC-152a 
blends, light saturated hydrocarbons C3-C6 \34\ and methyl formate, 
with respective GWPs of 124, less than one, \35\ three to 110,\36\ less 
than one,\37\ and 11.\38\
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    \34\ That is, alkanes with three to six carbons such as butane, 
n-pentane, isopentane, and cyclopentane.
    \35\ WMO, 2018.
    \36\ HFO-1336mzz(Z) and HFC-152a, have GWPs of about two (WMO, 
2018) and 124 (IPCC, 2007), respectively. If these values are 
weighted by mass percentage, then the blends range in GWP from about 
three to about 110.
    \37\ WMO, 2018.
    \38\ WMO, 2018.
---------------------------------------------------------------------------

    Information regarding the flammability and toxicity of other 
acceptable alternatives is provided in the listing decisions previously 
made (see https://www.epa.gov/snap/substitutes-polystyrene-extruded-boardstock-and-billet). Flammability and toxicity risks of the HFC-
134a/HFO-1234ze(E), the CO2/water/HFC-134a/HFO-1234ze(E) 
blends, and HFC-134a/HFC-152a/CO2/water blends are 
comparable to or lower than flammability and toxicity risks of other 
available substitutes in the same end-use. Toxicity risks can be 
minimized by use consistent with the AIHA WEELs, OSHA PEL, NIOSH STEL, 
recommendations in the manufacturer's SDSs, and other safety 
precautions common in the foam-blowing industry.

C. Status of Specific HFC Blends

    The existing SNAP listings in appendix U to 40 CFR subpart G 
include an unacceptable listing for XPS for ``HFC-134a, HFC-245fa, HFC-
365mfc, and blends thereof; Formacel TI, Formacel B, and Formacel Z-6'' 
under which those alternatives are ``unacceptable as of January 1, 
2021, except where allowed under a narrowed use limit.'' In the 2020 
NPRM, EPA proposed to revise this listing of unacceptable substitutes 
for XPS to add an exception to the unacceptability of blends of HFC-
134a, HFC-245fa, or HFC-365mfc for cases ``where blends are 
specifically listed as acceptable.'' 85 FR 35889. That change was 
proposed to allow for consistency between the proposed acceptable 
listings for these blends for XPS in the 2020 NPRM and the existing 
unacceptable listing for HFC-134a, HFC-245fa, HFC-365mfc, and blends 
thereof; and Formacel TI, Formacel B, and Formacel Z-6. EPA notes that 
if we finalize the proposed change of listing the three blends of HFC-
134a as ``acceptable, subject to narrowed use limits,'' no change would 
be needed to appendix U for consistency, as the existing listing 
already includes the text ``except where allowed under a narrowed use 
limit.''

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 a significant regulatory action that was submitted 
to the Office of Management and Budget (OMB) for review. Any changes 
made in response to OMB recommendations have been documented in the 
docket.

B. Paperwork Reduction Act (PRA)

    This action does not impose any new information collection burden 
under the PRA. OMB has previously approved the information collection 
activities contained in the existing regulations and has assigned OMB 
control number 2060-0226. The approved Information Collection Request 
includes five types of respondent reporting and recordkeeping 
activities pursuant to SNAP regulations: Submission of a SNAP petition, 
filing a Toxic Substances Control Act/SNAP Addendum, notification for 
test marketing activity, recordkeeping for substitutes acceptable 
subject to use restrictions, and recordkeeping for small volume uses. 
This rule contains no new requirements for reporting or recordkeeping.

C. Regulatory Flexibility Act (RFA)

    I certify that this action will not have a significant economic 
impact on a substantial number of small entities under the RFA. This 
action will not impose any requirements on small entities. The 
companies that may consider using the proposed blends, manufacturers of 
XPS products, are not small businesses.

D. Unfunded Mandates Reform Act (UMRA)

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

E. Executive Order 13132: Federalism

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

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

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

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

    This action is not subject to Executive Order 13045 because it is 
not economically significant as defined in Executive Order 12866, and 
because EPA does not believe the environmental health or safety risks 
addressed by this action present a disproportionate risk to children. 
The EPA has not conducted a separate analysis of risks to infants and 
children associated with this rule. Any risks to children are not 
different than the risks to the general population. This action's 
health and risk assessments are contained in the comparisons of 
toxicity for the various substitutes, as well as in the risk screens 
for the substitutes that are proposed to be listed. The risk screens 
are in the docket for this rulemaking.

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

    This action is not a ``significant energy action'' because it is 
not likely to

[[Page 55558]]

have a significant adverse effect on the supply, distribution, or use 
of energy. The blowing agents proposed in this action would enable the 
continued manufacture of insulation foam that maintain current levels 
of thermal efficiency.

I. National Technology Transfer and Advancement Act

    This rulemaking does not involve technical standards.

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

    A regulatory action may involve potential environmental justice 
concerns if it could (1) create new disproportionate impacts on 
minority populations, low-income populations, and/or indigenous 
peoples; (2) exacerbate existing disproportionate impacts on minority 
populations, low-income populations, and/or indigenous peoples; or (3) 
present opportunities to address existing disproportionate impacts on 
minority populations, low-income populations, and/or indigenous peoples 
through the action under development.
    In EPA's 2009 and 2016 Endangerment Findings, the Administrator 
considered climate change risks to minority populations and low-income 
populations, finding that certain parts of the population may be 
especially vulnerable based on their characteristics or circumstances, 
including the poor, the elderly, the very young, those already in poor 
health, the disabled, those living alone, and/or indigenous populations 
dependent on one or limited resources due to factors including but not 
limited to geography, access, and mobility. More recent assessment 
reports by the U.S. Global Change Research Program (USGCRP), the 
Intergovernmental Panel on Climate Change (IPCC), and the National 
Research Council of the National Academies (NRC) demonstrate that the 
potential impacts of climate change raise environmental justice issues. 
These reports concluded that poorer communities can be especially 
vulnerable to climate change impacts because they tend to have more 
limited adaptive capacities and are more dependent on climate-sensitive 
resources such as local water and food supplies. In corollary, some 
communities of color--specifically, populations defined jointly by both 
ethnic/racial characteristics and geographic location--may be uniquely 
vulnerable to climate change health impacts in the United States. 
Native American tribal communities possess unique vulnerabilities to 
climate change, particularly those impacted by degradation of natural 
and cultural resources within established reservation boundaries and 
threats to traditional subsistence lifestyles. Tribal communities whose 
health, economic well-being, and cultural traditions that depend upon 
the natural environment will likely be affected by the degradation of 
ecosystem goods and services associated with climate change.
    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 (February 16, 1994; 59 FR 7629). In 
light of the controls on production and consumption of HFCs under the 
American Innovation and Manufacturing Act (December 27, 2020; Pub. 
L.116-260), if the proposed listings were finalized, they would not be 
expected to change the overall amount of HFCs manufactured or imported 
in the United States or to adversely impact the climate. Additionally, 
this limited action does not present a meaningful opportunity to 
address existing disproportionate impacts.
    EPA's analysis indicates that other environmental impacts and human 
health impacts of the proposed substitutes are comparable to or less 
than those of other substitutes that are listed as acceptable for the 
same end-use. For EPA's analysis of the human health and environmental 
impacts of these substitutes, see the risk screens in the public docket 
for this rulemaking (ICF, 2020a; ICF, 2020b; ICF, 2020c). The limited 
period of time for the proposed listings in this supplemental proposal 
would further reduce any impacts compared to the proposed listings for 
XPS in the 2020 NPRM. Based on these considerations, EPA expects that, 
if this supplemental proposal becomes final as proposed, the effects on 
minority populations, low-income populations, and/or indigenous peoples 
would not be disproportionately high and adverse.

VI. References

    Unless specified otherwise, all documents are available 
electronically through the Federal Docket Management System, Docket 
number EPA-HQ-OAR-2019-0698.

Bellair and Hood, 2019. Bellair, R.J. and Hood, L. Comprehensive 
evaluation of the flammability and ignitability of HFO-1234ze. 
Process Safety and Environmental Protection 132, 273-284. Available 
online at doi.org/10.1016/j.psep.2019.09.033.
DuPont, 2019a. August 23, 2019. Letter from DuPont Performance 
Building Solutions to EPA. Docket ID EPA-HQ-OAR-2019-0698-0007.
DuPont, 2019b. December 17, 2019 Letter from DuPont Performance 
Building Solutions to EPA. Docket ID EPA-HQ-OAR-2019-0698-0008.
DuPont, 2020a. August 23, 2020. DuPont Performance Building 
Solutions. SNAP Rule 23 Discussion with EPA.
DuPont, 2020b. November 20, 2020 Letter from J. Hansbro, DuPont 
Performance Building Solutions, to C. Grundler and C. Newberg, EPA.
FTOC, 2018. 2018 Report of the Rigid and Flexible Foams Technical 
Options Committee. 2018 Assessment Report. Available online at 
https://ozone.unep.org/science/assessment/teap.
ICF, 2020a. Risk Screen on Substitutes in Extruded Polystyrene 
Boardstock and Billet Foam; Substitute: Blends of 40 to 52 Percent 
HFC-134a by Weight and the Remainder HFO-1234ze(E) (HFC-HFO Co-
blowing Agents).
ICF, 2020b. Risk Screen on Substitutes in Extruded Polystyrene 
Boardstock and Billet Foam; Substitute: Blends of 40 to 52 Percent 
HFC-134a with 40 to 60 Percent HFO-1234ze(E) and 10 to 20 Percent 
Each Water and CO2 by Weight (Co-blowing Blends).
ICF, 2020c. Risk Screen on Substitutes in Extruded Polystyrene 
Boardstock and Billet Foam; Substitute: Blends with Maximum of 51 
Percent HFC-134a, 17 to 41 Percent HFC-152a, up to 20 Percent 
CO2 and One to 13 Percent Water (Blends for Foam 
Blowing).
Industrial Science & Technology Network, Inc. 2016. Final Scientific 
Report for DOE/EERE, A New Generation of Building Insulation by 
Foaming Polymer Blend Materials with CO2. Industrial 
Science & Technology Network, Inc. Available online at: https://www.osti.gov/servlets/purl/1244652.
IPCC, 2007. Climate Change 2007: The Physical Science Basis. 
Contribution of Working Group I to the Fourth Assessment Report of 
the Intergovernmental Panel on Climate Change. Solomon, S., Qin, D., 
Manning, M., Chen, Z., Marquis, M., Averyt, K.B., Tignor, M., and 
Miller, H.L. (eds.). Cambridge University Press. Cambridge, United 
Kingdom and New York, NY, USA. Available online at: www.ipcc.ch/
publications_and_data/ar4/wg1/en/contents.html.
Sherwood et al. 2018. Sherwood, S.C., Vishal, D., and Salomez, C. 
(2018) The global warming potential of near-surface emitted water 
vapour. Environ. Res. Lett.,13 104006. Available online at https://iopscience.iop.org/article/10.1088/1748-9326/aae018/pdf.
WMO (World Meteorological Organization), Scientific Assessment of 
Ozone Depletion: 2018, Global Ozone Research and Monitoring 
Project--Report No. 58, 588 pp., Geneva, Switzerland, 2018.

[[Page 55559]]

Available at: https://ozone.unep.org/sites/default/files/2019-05/SAP-2018-Assessment-report.pdf.

List of Subjects in 40 CFR Part 82

    Environmental protection, Administrative practice and procedure, 
Air pollution control, Reporting and recordkeeping requirements, 
Stratospheric ozone layer.

Michael S. Regan,
Administrator.
    For the reasons set forth in the preamble, EPA proposes to amend 40 
CFR part 82 as follows:

PART 82--PROTECTION OF STRATOSPHERIC OZONE

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

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

Subpart G--Significant New Alternatives Policy Program

0
2. In appendix W to subpart G of part 82:
0
a. Revise the heading for appendix W to subpart G of part 82.
0
b. Add a table titled ``Foam Blowing Agents--Substitutes Acceptable 
Subject to Narrowed Use Limits'' after the table titled 
``Refrigerants--Substitutes Acceptable Subject to Use Conditions''.
    The addition and revision read as follows:

Appendix W to Subpart G of Part 82--Substitutes Listed in the May 6, 
2021 Final Rule and the [Date of publication of final rule in the 
Federal Register] Final Rule--Effective June 7, 2021 and [Date 30 days 
after date of publication of the final rule in the Federal Register]

* * * * *

                   Foam Blowing Agents--Substitutes Acceptable Subject to Narrowed Use Limits
----------------------------------------------------------------------------------------------------------------
            End-use                Substitute         Decision       Narrowed use limits    Further information
----------------------------------------------------------------------------------------------------------------
Extruded Polystyrene:           Blends of 40 to   Acceptable        Acceptable from
 Boardstock and Billet.          52 percent HFC-   Subject to        [insert date 30 days
                                 134a by weight    Narrowed Use      after date of
                                 and the           Limits.           publication of final
                                 remainder HFO-                      rule] until January
                                 1234ze(E).                          1, 2023: only for
                                                                     use where reasonable
                                                                     efforts have been
                                                                     made to ascertain
                                                                     that other
                                                                     alternatives are not
                                                                     yet technically
                                                                     feasible for reasons
                                                                     of performance or
                                                                     safety.
                                                                    Users are required to
                                                                     document and retain
                                                                     the results of their
                                                                     technical
                                                                     investigation of
                                                                     alternatives for the
                                                                     purpose of
                                                                     demonstrating
                                                                     compliance.
                                                                     Information shall
                                                                     include descriptions
                                                                     of:
                                                                     Process or
                                                                     product in which the
                                                                     substitute is
                                                                     needed;
                                                                     Substitutes
                                                                     examined and
                                                                     rejected;
                                                                     Reason for
                                                                     rejection of other
                                                                     alternatives, e.g.,
                                                                     performance,
                                                                     technical or safety
                                                                     standards; and/or
                                                                     Anticipated
                                                                     date other
                                                                     substitutes will be
                                                                     available and
                                                                     projected time for
                                                                     switching.
Extruded Polystyrene:           Blends of 40 to   Acceptable        Acceptable from
 Boardstock and Billet.          52 percent HFC-   Subject to        [insert date 30 days
                                 134a with 40 to   Narrowed Use      after date of
                                 60 percent HFO-   Limits.           publication of final
                                 1234ze(E) and                       rule] until January
                                 10 to 20                            1, 2023: Only for
                                 percent each                        use where reasonable
                                 water and CO2                       efforts have been
                                 by weight.                          made to ascertain
                                                                     that other
                                                                     alternatives are not
                                                                     yet technically
                                                                     feasible for reasons
                                                                     of performance or
                                                                     safety.
                                                                    Users are required to
                                                                     document and retain
                                                                     the results of their
                                                                     technical
                                                                     investigation of
                                                                     alternatives for the
                                                                     purpose of
                                                                     demonstrating
                                                                     compliance.
                                                                     Information shall
                                                                     include descriptions
                                                                     of:.
                                                                     Process or
                                                                     product in which the
                                                                     substitute is
                                                                     needed;
                                                                     Substitutes
                                                                     examined and
                                                                     rejected;
                                                                     Reason for
                                                                     rejection of other
                                                                     alternatives, e.g.,
                                                                     performance,
                                                                     technical or safety
                                                                     standards; and/or
                                                                     Anticipated
                                                                     date other
                                                                     substitutes will be
                                                                     available and
                                                                     projected time for
                                                                     switching.
Extruded Polystyrene:           Blends with       Acceptable        Acceptable from
 Boardstock and Billet.          maximum of 51     Subject to        [insert date 30 days
                                 percent HFC-      Narrowed Use      after date of
                                 134a, 17 to 41    Limits.           publication of final
                                 percent HFC-                        rule] until January
                                 152a, up to 20                      1, 2023 only for use
                                 percent CO2 and                     where reasonable
                                 one to 13                           efforts have been
                                 percent water.                      made to ascertain
                                                                     that other
                                                                     alternatives are not
                                                                     yet technically
                                                                     feasible for reasons
                                                                     of performance or
                                                                     safety.
                                                                    Users are required to
                                                                     document and retain
                                                                     the results of their
                                                                     technical
                                                                     investigation of
                                                                     alternatives for the
                                                                     purpose of
                                                                     demonstrating
                                                                     compliance.
                                                                     Information shall
                                                                     include descriptions
                                                                     of:.
                                                                     Process or
                                                                     product in which the
                                                                     substitute is
                                                                     needed;
                                                                     Substitutes
                                                                     examined and
                                                                     rejected;

[[Page 55560]]

 
                                                                     Reason for
                                                                     rejection of other
                                                                     alternatives, e.g.,
                                                                     performance,
                                                                     technical or safety
                                                                     standards; and/or
                                                                     Anticipated
                                                                     date other
                                                                     substitutes will be
                                                                     available and
                                                                     projected time for
                                                                     switching.
----------------------------------------------------------------------------------------------------------------

[FR Doc. 2021-21031 Filed 10-5-21; 8:45 am]
BILLING CODE 6560-50-P