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 Environmental Protection Agency 40 CFR Part 82
[EPA-HQ-OAR-2003-0118; FRL-9445-01-OAR]
RIN 2060-AG12
 AGENCY: Environmental Protection Agency (EPA).
 ACTION: Determination of acceptability.
 SUMMARY: This determination of acceptability expands the list of acceptable substitutes pursuant to the U.S. Environmental Protection Agency's Significant New Alternatives Policy program. This action lists as acceptable additional substitutes for use in the refrigeration and air conditioning; foam blowing; aerosols; cleaning solvents; and adhesives, coatings, and inks sectors.
 DATES: This determination is applicable on January 20, 2022.
 ADDRESSES: EPA established a docket for this action under Docket ID No. EPA-HQ-OAR-2003-0118 (continuation of Air Docket A-91-42). All electronic documents in the docket are listed in the index at 
                        *www.regulations.gov.*
                         Although listed in the index, some information is not publicly available, 
                        *i.e.,*
                         Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. Publicly available docket materials are available either electronically at 
                        *www.regulations.gov*
                         or in hard copy at the EPA Air Docket (Nos. A-91-42 and EPA-HQ-OAR-2003-0118), EPA Docket Center (EPA/DC), William J. Clinton West, Room 3334, 1301 Constitution Avenue NW, Washington, DC 20460. The telephone number for the Public Reading Room is (202) 566-1744, and the telephone number for the Air Docket is (202) 566-1742. Out of an abundance of caution for members of the public and our staff, the EPA Docket Center and Reading Room are closed to 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. 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: Gerald Wozniak by telephone at (202) 343-9624, by email at 
                        *Wozniak.gerald@epa.gov,*
                         or by mail at U.S. Environmental Protection Agency, Mail Code 6205T, 1200 Pennsylvania Avenue NW, Washington, DC 20460. Overnight or courier deliveries should be sent to the office location at 1201 Constitution Avenue NW, Washington, DC 20004.


SUPPLEMENTARY INFORMATION: Table of Contents I. Listing of New Acceptable Substitutes A. Refrigeration and Air Conditioning B. Foam Blowing C. Aerosols D. Cleaning Solvents E. Adhesives, Coatings, and Inks Appendix A: Summary of Decisions for New Acceptable Substitutes I. Listing of New Acceptable Substitutes This action is listing as acceptable additional substitutes for use in the refrigeration and air conditioning; foam blowing; aerosols; cleaning solvents; and adhesives, coatings and inks sectors. This action presents EPA's most recent decision under the Significant New Alternatives Policy (SNAP) program to list as acceptable several substitutes in different end-uses. New substitutes are: Hydrochlorofluoroolefin (HCFO)-1233zd(E) in cold storage warehouses,( print page 3038)
                    ice skating rinks and industrial process air conditioning (new equipment only);
                Blends of 10 to 90 percent hydrofluoroolefin (HFO)-1234ze(E) by weight and the remainder HCFO-1233zd(E) in polystyrene: Extruded boardstock and billet (XPS);
                Blends of 10 to 90 percent HFO-1234ze(E) by weight and the remainder hydrofluorocarbon (HFC)-152a in XPS;
                Blends of zero to 100 percent HFO-1234ze(E), zero to 70 percent methyl formate, zero to 60 percent HFC-152a, zero to 60 percent carbon dioxide (CO2), and zero to 60 percent water in XPS; and
                HCFO-1233yd(Z) in electronics cleaning, metals cleaning, precision cleaning, aerosol solvents, and coatings. EPA's review of certain substitutes listed in this document is pending for other end-uses. Listing decisions in the end-uses in this document do not prejudge EPA's listings of these substitutes for other end-uses. While certain substitutes being added through this action to the acceptable lists for specific end-uses may have a higher risk in one or more SNAP criteria than certain other substitutes already listed as acceptable or acceptable subject to restrictions, they have a similar or lower overall risk than other acceptable substitutes in those end-uses. For additional information on SNAP, 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 the industrial sectors covered by the SNAP program 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 March 18, 1994 (59 FR 13044), and the regulations 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. The sections below discuss each substitute listing in detail. Appendix A contains tables summarizing each listing decision in this action. The statements in the “Further Information” column in the tables provide additional information but these are not legally binding under section 612 of the Clean Air Act (CAA). Although you are not required to follow recommendations in the “Further Information” column of the table under section 612 of the CAA, some of these statements may refer to obligations that are enforceable or binding under federal or state programs other than the SNAP program. The identification of other enforceable or binding requirements should not be construed as a comprehensive list of such obligations. In many instances, the information simply refers to standard operating practices in existing industry standards and/or building codes. When using these substitutes in the identified end-use, EPA strongly encourages you to apply the information in the “Further Information” column. Many of these recommendations, if adopted, would not require significant changes to existing operating practices. You can find submissions to EPA for the substitutes listed in this document, as well as other materials supporting the decisions in this action, in Docket EPA-HQ-OAR-2003-0118 at 
                    *www.regulations.gov.* A. Refrigeration and Air Conditioning 1. HCFO-1233zd(E) *EPA's decision: EPA finds HCFO-1233zd(E) acceptable as a substitute for use in:* Cold storage warehouses (new equipment only)
                Ice skating rinks (new equipment only)
                Industrial process air conditioning (new equipment only) HCFO-1233zd(E), marketed under the trade name Solstice®zd, is also known as 
                    *trans*
                    -1-chloro-3,3,3-trifluoroprop-1-ene (Chemical Abstracts Service Registry Number [CAS Reg. No.] 102687-65-0). You may find a copy of the applicant's submission, with CBI redacted, providing the required health and environmental information for this substitute in this end-use in Docket EPA-HQ-OAR-2003-0118 at 
                    *www.regulations.gov*
                     under the name, “Supporting Materials for Notice 37 Listing of HCFO-1233zd(E) in Refrigeration and Air Conditioning. SNAP Submission Received October 7, 2019.” EPA performed an assessment to examine the health and environmental risks of this substitute. These assessments are available in Docket EPA-HQ-OAR-2003-0118: “Risk Screen on Substitutes in Cold Storage Warehouses and Industrial Process Air Conditioning. Substitute: HCFO-1233zd(E).”
                “Risk Screen on Substitutes in Ice Skating Rinks. Substitute: HCFO-1233zd(E).” EPA previously listed HCFO-1233zd(E) as acceptable for use in several refrigeration and air conditioning and foam blowing end-uses (December 11, 2020, 85 FR 79863; August 10, 2012, 77 FR 47768; October 21, 2014, 79 FR 62863). *Environmental information:*
                     HCFO-1233zd(E) has an ozone depletion potential (ODP) of less than 0.0004 and a global warming potential (GWP) of 3.7.[1]
                    
                     HCFO-1233zd(E) is excluded from the definition of volatile organic compounds (VOC) under CAA regulations (see 40 CFR 51.100(s)) addressing the development of state implementation plans (SIPs) to attain and maintain the National Ambient Air Quality Standards (NAAQS). Knowingly venting or releasing this refrigerant blend is limited by the venting prohibition under section 608(c)(2) of the CAA, codified in EPA's regulations at 40 CFR 82.154(a). *Flammability information:*
                     HCFO-1233zd(E) is not flammable. *Toxicity and exposure data:*
                     Potential health effects of exposure to this substitute include drowsiness or dizziness. The substitute may also irritate the skin or eyes or cause frostbite. The substitute could cause asphyxiation if air is displaced by vapors in a confined space. These potential health effects are common to many refrigerants. The Workplace Environmental Exposure Limit (WEEL) Committee of the Occupational Alliance for Risk Science (OARS) has established a WEEL of 800 ppm on an eight-hour time-weighted average (8-hr TWA) for HCFO-1233zd(E). EPA anticipates that users will be able to meet the WEEL and address potential health risks by following requirements and recommendations in the manufacturer's safety data sheet (SDS), American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) Standard 15, and other safety precautions common to the refrigeration and air conditioning industry. *Comparison to other substitutes in these end-uses:*
                     HCFO-1233zd(E) has an ODP of less than 0.0004, comparable to or less than other listed substitutes in these end-uses with ODPs ranging from zero to 0.098. For cold storage warehouses, HCFO-1233zd(E)'s GWP of about 3.7 is comparable to or lower than that of 
                    ( print page 3039)
                    other acceptable substitutes for new equipment such as ammonia absorption, CO2
                    , R-450A, R-513A, and R-407C, with GWPs [2]
                    
                     ranging from zero to 1,770. For ice skating rinks and industrial process air conditioning, HCFO-1233zd(E)'s GWP of about 3.7 is comparable to or lower than that of other acceptable substitutes for new equipment such as ammonia absorption, CO2, R-450A, R-513A, and R-507A, with GWPs ranging from zero to 3,990. Flammability and toxicity risks are comparable to or lower than flammability and toxicity risks of other available substitutes in the same end-uses. Toxicity risks can be minimized by use consistent with the OARS WEEL, ASHRAE 15, and other industry standards, recommendations in the manufacturer's SDS, and other safety precautions common in the refrigeration and air conditioning industry. EPA finds HCFO-1233zd(E) acceptable in the cold storage warehouses (new equipment only), ice skating rinks (new equipment only) and industrial process air conditioning (new equipment only) end-uses because it does not pose greater overall environmental and human health risk than other available substitutes in the same end-uses. B. Foam Blowing 1. Blends of 10 to 90 Percent HFO-1234ze(E) by Weight and the Remainder HCFO-1233zd(E) E
                    *PA's decision: EPA finds blends of 10 to 90 percent HFO-1234ze(E) by weight and the remainder HCFO-1233zd(E) acceptable as a substitute for use as a blowing agent in:* *Polystyrene:*
                     Extruded boardstock and billet These blends range in composition from 10 percent HFO-1234ze(E) and 90 percent HCFO-1233zd(E) to 90 percent HFO-1234ze(E) and 10 percent HCFO-1233zd(E). Accordingly, these blends are referred to as blends of 10 to 90 percent by weight HFO-1234ze(E) and the remainder HCFO-1233zd(E), or hereafter in this action as “HFO-1234ze(E)/HCFO-1233zd(E) co-blowing blends”; they also go by the trade name of Solstice® XBA-1. HFO-1234ze(E) is also called 1,3,3,3-tetrafluoropropene (E), or 
                    *trans*
                    -1,3,3,3-tetrafluoropropene (CAS Reg. No. 29118-24-9). HCFO-1233zd(E) is also called 
                    *trans*
                    -1-chloro-3,3,3-trifluoro-prop-1-ene (CAS Reg. No. 102687-65-0). You may find a copy of the applicant's submission, with CBI redacted, providing the required health and environmental information for this substitute in this end-use in Docket EPA-HQ-OAR-2003-0118 at 
                    *www.regulations.gov*
                     under the name, “Supporting Materials for Notice 37 Listing Blends of 10 to 90 Percent HFO-1234ze(E) by Weight and the Remainder HCFO-1233zd(E) as a Foam Blowing Agent. SNAP Submission Received November 4, 2019.” EPA has performed an assessment to examine the health and environmental risks of this substitute. This assessment is available in docket EPA-HQ-OAR-2003-0118 under the name “Risk Screen on Substitutes in Extruded Polystyrene Boardstock and Billet Foam Substitute: Blends of 10 to 90 Percent HFO-1234ze(E) by Weight and the Remainder HCFO-1233zd(E) (Solstice® XBA-1).” *Environmental information:*
                     HFO-1234ze(E) has an ODP of zero and HCFO-1233zd(E) has an ODP of less than 0.0004.[3]
                    
                     If these values are weighted by mass percentage, then these HFO-1234ze(E)/HCFO-1233zd(E) co-blowing blends have an ODP ranging from less than 0.0004 to less than 0.00004. Their components, HFO-1234ze(E) and HCFO-1233zd(E), have GWPs of less than one [4]
                    
                     and 3.7, respectively. If these values are weighted by mass percentage, then the blends range in GWP from about 1.3 to about 3.4. Both components of the blends are excluded from the definition of VOC under CAA regulations (see 40 CFR 51.100(s)) addressing the development of SIPs to attain and maintain the NAAQS. *Flammability information:*
                     The component HCFO-1233zd(E) is non-flammable. HFO-1234ze(E) is not flammable at standard temperature and pressure using the standard test method American Society for Testing and Materials (ASTM) E681. However, at higher temperatures, such as the temperatures typical for extruding XPS, HFO-1234ze(E) may also be flammable, particularly at higher humidity levels.[5] *Toxicity and exposure data:*
                     Potential health effects of these substitutes at lower concentrations include drowsiness and dizziness. Potential health effects also include skin or eye irritation or frostbite. The components of HFO-1234ze(E)/HCFO-1233zd(E) co-blowing blends can cause symptoms of asphyxiation when present at sufficiently high concentrations. Excessive inhalation of the substitute may also result in an irregular heartbeat, due to cardiac effects. These potential health effects are common to many foam blowing agents. The American Industrial Hygiene Association (AIHA) has established a WEEL of 800 ppm as an 8-hr TWA for HFO-1234ze(E), and OARS's WEEL committee has established a WEEL of 800 ppm for HCFO-1233zd(E). EPA anticipates that users will be able to meet the AIHA and OARS WEELs and address potential health risks by following requirements and recommendations in the manufacturer's SDSs and other safety precautions common to the foam blowing industry. *Comparison to other substitutes in this end-use:*
                     These HFO-1234ze(E)/HCFO-1233zd(E) co-blowing blends have an ODP ranging from less than 0.0004 to less than 0.00004, 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 (hereafter in this action “HFO-1336mzz(Z)/HFC-152a blends”), HFO-1234ze(E), methyl formate, and CO2.
                     These HFO-1234ze(E)/HCFO-1233zd(E) blends' GWPs from about 1.3 to 3.4 are lower than or comparable to those of other acceptable substitutes in the same end-use for which we are finding it acceptable, such as HFO-1336mzz(Z)/HFC-152a blends, HFO-1234ze(E), light saturated hydrocarbons C3-C6 [6]
                    
                     and methyl formate, with respective GWPs 
                    ( print page 3040)
                    of approximately three to 110,[7]
                    
                     124, one,[8]
                    
                     less than one,[9]
                    
                     and 11.[10] Flammability and toxicity risks are comparable to or lower than flammability and toxicity risks of other available substitutes in the same end-use. Some acceptable substitutes in this end-use are flammable, like HFC-152a, light saturated hydrocarbons C3-C6, and methyl formate, while others are non-flammable. Toxicity risks can be minimized by use consistent with the AIHA's and OARS's WEELs, recommendations in the SDS, and other safety precautions common in the foam blowing industry. EPA finds blends of 10 to 90 percent by weight HFO-1234ze(E) and the remainder HCFO-1233zd(E) acceptable in the XPS end-use because they do not pose greater overall environmental and human health risk than other available substitutes in the same end-use. 2. Blends of 10 to 90 Percent HFO-1234ze(E) by Weight and the Remainder HFC-152a *EPA's decision: EPA finds blends of 10 to 90 percent HFO-1234ze(E) by weight and the remainder HFC-152a acceptable as a substitute for use as a blowing agent in:* *Polystyrene:*
                     Extruded boardstock and billet These blends range in composition from 10 percent HFO-1234ze(E) and 90 percent HFC-152a to 90 percent HFO-1234ze(E) and 10 percent HFC-152a. Accordingly, these blends are also referred to as blends of 10 to 90 percent by weight HFO-1234ze(E) and the remainder HFC-152a, or hereafter in this action as “HFO-1234ze(E)/HFC-152a co-blowing blends”; they also go by the trade name of Solstice® XBA-2. HFO-1234ze(E) is also called 1,3,3,3-tetrafluoropropene (E), or 
                    *trans*
                    -1,3,3,3-tetrafluoropropene (CAS Reg. No. 29118-24-9). HFC-152a is also called 1,1-difluoroethane (CAS Reg. No. 75-37-6). You may find a copy of the applicant's submission, with CBI redacted, providing the required health and environmental information for this substitute in this end-use in Docket EPA-HQ-OAR-2003-0118 at 
                    *www.regulations.gov*
                     under the name, “Supporting Materials for Notice 37 Listing Blends of 10 to 90 Percent HFO-1234ze(E) by Weight and the Remainder HFC-152a as a Foam Blowing Agent. SNAP Submission Received November 4, 2019.” EPA has performed an assessment to examine the health and environmental risks of this substitute. This assessment is available in docket EPA-HQ-OAR-2003-0118 under the name “Risk Screen on Substitutes in Extruded Polystyrene Boardstock and Billet Foam Substitute: Blends of 10 to 90 Percent HFO-1234ze(E) by Weight and the Remainder HFC-152a (Solstice® XBA-2).” *Environmental information:*
                     These HFO-1234ze(E)/HFC-152a co-blowing blends and their components have an ODP of zero. Their components, HFO-1234ze(E) and HFC-152a, have GWPs of less than one [11]
                    
                     and 124, respectively. If these values are weighted by mass percentage, then the blends range in GWP from about 13 to about 112. Both components of the blends are excluded from the definition of VOC under CAA regulations (see 40 CFR 51.100(s)) addressing the development of SIPs to attain and maintain the NAAQS. *Flammability information:*
                     The component HFC-152a is flammable while the component HFO-1234ze(E) is not 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, HFO-1234ze(E) may also be flammable, particularly at higher humidity levels.[12] *Toxicity and exposure data:*
                     Potential health effects of these substitutes at lower concentrations include drowsiness and dizziness. Potential health effects also include skin or eye irritation or frostbite. The components of HFO-1234ze(E)/HFC-152a blends can cause symptoms of asphyxiation when present at sufficiently high concentrations. Excessive inhalation of the substitute may also result in an irregular heartbeat, due to cardiac effects. These potential health effects are common to many foam blowing agents. The AIHA has established WEELs of 1,000 ppm for HFC-152a, and of 800 ppm for HFO-1234ze(E), both as an 8-hr TWA. EPA anticipates that users will be able to meet the AIHA WEELs and address potential health risks by following requirements and recommendations in the manufacturer's SDSs and other safety precautions common to the foam blowing industry. *Comparison to other substitutes in this end-use:*
                     These HFO-1234ze(E)/HFC-152a co-blowing blends have an ODP of zero, comparable to all other acceptable substitutes in this end-use, such as HFO-1336mzz(Z)/HFC-152a blends, HFC-152a, HFO-1234ze(E), methyl formate, and CO2.
                     These HFO-1234ze(E)/HFC-152a co-blowing blends' GWPs from about 13 to 112 are lower than or comparable to those of other acceptable substitutes in the same end-use for which we are finding them acceptable, such as HFO-1336mzz(Z)/HFC-152a blends and HFC-152a with respective GWPs of approximately three to 110 [13]
                    
                     and 124. The GWPs of the HFO-1234ze(E)/HFC-152a co-blowing blends of about 13 to 112 are higher than those for acceptable alternatives such as HFO-1234ze(E), light saturated hydrocarbons C3-C6 and methyl formate, with respective GWPs of one,[14]
                    
                     less than one,[15]
                    
                     and 11.[16]
                    
                     Based on current information, EPA anticipates that HFO-1234ze(E), light saturated hydrocarbons C3-C6 and methyl formate are not currently being used as the sole blowing agent by any U.S. manufacturers in this end-use because the individual chemicals have drawbacks such as insufficient vapor pressure, insufficient solubility in the polystyrene matrix, or high permeability resulting in low thermal resistance (“R-value”); blends such as these HFO-1234ze(E)/HFC-152a co-blowing blends are expected to result in a feasible balance of blowing agent properties for adequate or better performance. Flammability and toxicity risks are comparable to or lower than flammability and toxicity risks of other available substitutes in the same end-use. Some acceptable substitutes in this end-use are flammable, like HFC-152a, light saturated hydrocarbons C3-C6, and methyl formate, while others are non-flammable. Toxicity risks can be minimized by use consistent with the 
                    ( print page 3041)
                    AIHA's WEELs, recommendations in the SDS, and other safety precautions common in the foam blowing industry. EPA finds blends of 10 to 90 percent by weight HFO-1234ze(E) and the remainder HFC-152a acceptable in the XPS end-use because they do not pose greater overall environmental and human health risk than other available substitutes in the same end-use. 3. Blends of Zero to 100 Percent HFO-1234ze(E), Zero to 70 Percent Methyl Formate, Zero to 60 Percent HFC-152a, Zero to 60 Percent CO2
                     and Zero to 60 Percent Water *EPA's decision: EPA finds blends of zero to 100 percent HFO-1234ze(E), zero to 70 percent methyl formate, zero to 60 percent HFC-152a, zero to 60 percent CO**2**and zero to 60 percent water acceptable as a substitute for use as a blowing agent in:* *Polystyrene:*
                     Extruded boardstock and billet These blends are hereafter referred to as “HFO-1234ze(E)/methyl formate/HFC-152a/CO2
                    /water co-blowing blends.” The components of the blends are co-blown and component percentages are by weight. HFO-1234ze(E) is also known as HFC-1234ze, HFO-1234ze or 
                    *trans-*
                    1,3,3,3-tetrafluoroprop-1-ene (CAS Reg. No. 29118-24-9). Methyl formate is also known as methyl methanoate or formic acid, methyl ester (CAS Reg. No. 107-31-3). HFC-152a, also known as 1,1-difluoroethane, has CAS Reg. No. 75-37-6. CO2
                     has CAS Reg. No. 124-38-9, and water has CAS Reg. No. 7732-18-5. You may find a copy of the applicant's submission, with CBI redacted, providing the required health and environmental information for this substitute in this end-use in Docket EPA-HQ-OAR-2003-0118 at 
                    *www.regulations.gov*
                     under the name, “Supporting Materials for Notice 37 Listing Blends of 0-100% HFO-1234ze(E), 0-70% Methyl Formate, 0-60% HFC-152a, 0-60% CO2
                     and 0-60% Water as a Foam Blowing Agent. SNAP Submission Received January 26, 2021.” EPA has performed an assessment to examine the health and environmental risks of this substitute. This assessment is available in docket EPA-HQ-OAR-2003-0118 under the name “Risk Screen on Substitutes in Extruded Polystyrene Boardstock and Billet Foam Substitute: HFO-1234ze(E)/Methyl Formate/HFC-152a/CO2
                    /Water Co-blowing Blends for Extruded Polystyrene Foam Insulation (HFO-1234ze(E)/Methyl Formate/HFC-152a/CO2
                    /Water Co-blowing Blends).” *Environmental information:*
                     The blends have an ODP of zero. Their components, HFO-1234ze(E), methyl formate, HFC-152a, CO2,
                     and water have GWPs of one,[17]
                    
                     11,[18]
                    
                     124,[19]
                    
                     one,[20]
                    
                     and less than one,[21]
                    
                     respectively. If these values are weighted by mass percentage, then the blends could have a GWP ranging from one to 80. HFO-1234ze(E), methyl formate, HFC-152a, CO2, and water—components of the blends—are excluded from EPA's regulatory definition of VOC under CAA regulations that address the development of SIPs to attain and maintain the NAAQS. 
                    *See*40 CFR 51.100(s). *Flammability information:*
                     The components HFC-152a and methyl formate are flammable while 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, HFO-1234ze(E) may also be flammable, particularly at higher humidity levels.[22] *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. Excessive inhalation of the substitutes may also result in an irregular heartbeat, due to cardiac effects. 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 AIHA has established WEELs of 1,000 ppm as an eight-hour time-weighted average for HFC-152a and 800 ppm for HFO-1234ze(E). Methyl formate has an Occupational Safety and Health Administration (OSHA) permissible exposure limits (PEL) of 100 ppm on an 8-hr TWA. CO2
                     has an OSHA PEL of 5,000 ppm on an 8-hr TWA, 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 PELs, and NIOSH STEL and address potential health risks by following requirements and recommendations in the manufacturer's SDSs and other safety precautions common to the foam blowing industry. *Comparison to other substitutes in this end-use:*
                     HFO-1234ze(E)/methyl formate/HFC-152a/CO2
                    /water co-blowing blends have ODPs of zero, comparable to all other acceptable substitutes in this end-use, such as HFO-1336mzz(Z)/HFC-152a blends, HFC-152a, HFO-1234ze(E), methyl formate, and CO2. The GWPs of the HFO-1234ze(E)/methyl formate/HFC-152a/CO2
                    /water co-blowing blends, ranging from approximately one to 80, are lower than HFC-152a's GWP of 124 and are comparable to or lower than those for HFO-1336mzz(Z)/HFC-152a blends (three to 110 [23]
                    
                    ). The worst-case GWPs of the HFO-1234ze(E)/methyl formate/HFC-152a/CO2
                    /water co-blowing blends are higher than those for acceptable alternatives such as HFO-1234ze(E), light saturated hydrocarbons C3-C6 and methyl formate, with respective GWPs of less than one,[24]
                    
                     less than one,[25]
                    
                     and 11,[26]
                    
                     while the GWP at the low end of the range of approximately one is comparable to those acceptable alternatives. Based on current information, EPA anticipates that HFO-1234ze(E), light saturated hydrocarbons C3-C6 and methyl formate are not currently being used as the sole blowing agent by any U.S. manufacturers in this end-use because the individual chemicals have drawbacks such as insufficient vapor pressure, insufficient solubility in the polystyrene matrix, or high permeability resulting in low thermal resistance (“R-value”); blends such as these HFO-1234ze(E)/methyl formate/HFC-152a/CO2
                    /water co-blowing blends are expected to result in a feasible balance of blowing agent 
                    ( print page 3042)
                    properties for adequate or better performance. Flammability and toxicity risks of the HFO-1234ze(E)/methyl formate/HFC-152a/CO2
                    /water co-blowing blends are comparable to or lower than flammability and toxicity risks of other available substitutes in the same end-use. Some acceptable substitutes in this end-use are flammable, like HFC-152a, light saturated hydrocarbons C3-C6, and methyl formate, while others are non-flammable. Toxicity risks can be minimized by use consistent with the AIHA WEELs, OSHA PELs, NIOSH STEL, recommendations in the manufacturer's SDSs, and other safety precautions common in the foam-blowing industry. EPA finds HFO-1234ze(E)/methyl formate/HFC-152a/CO2
                    /water co-blowing blends acceptable in the XPS end-use because they do not pose greater overall environmental and human health risk than other available substitutes in the same end-use. C. Aerosols 1. HCFO-1233yd(Z) *EPA's decision: EPA finds HCFO-1233yd(Z) acceptable as a substitute for use in:* Aerosol solvents HCFO-1233yd(Z) is also known as 
                    *(Z)-*
                    1-Chloro-2,3,3-trifluoropropene (CAS Reg. No. 1263679-68-0). You may find a copy of the applicant's submission, with CBI redacted, providing the required health and environmental information for this substitute in this end-use in Docket EPA-HQ-OAR-2003-0118 at 
                    *www.regulations.gov*
                     under the name, “Supporting Materials for Notice 37 Listing of HCFO-1233yd(Z) in Cleaning Solvents, Aerosol Solvents, and Coatings. SNAP Submission Received March 12, 2019.” EPA performed an assessment to examine the health and environmental risks of this substitute. This assessment is available in Docket EPA-HQ-OAR-2003-0118: “Risk Screen on Substitutes in Aerosol Solvents. Substitute: HCFO-1233yd(Z).” *Environmental information:*
                     HCFO-1233yd(Z) has an ODP of 0.00003 and a GWP of less than 1.[27]
                    
                     Under CAA regulations (see 40 CFR 51.100(s)) defining VOC for the purpose of addressing the development of SIPs to attain and maintain the NAAQS, HCFO-1233yd(Z) would be considered a VOC. That definition provides that “any compound of carbon” which “participates in atmospheric photochemical reactions” is considered a VOC unless expressly excluded in that provision based on a determination of “negligible photochemical reactivity.” The manufacturer has petitioned EPA to exclude HCFO-1233yd(Z) from the definition of VOC under those regulations. EPA has not yet taken action on that petition. This substitute is subject to a Toxic Substance Control Act (TSCA) section 5(a)(2) Significant New Use Rule (SNUR). *Flammability information:*
                     HCFO-1233yd(Z) is not flammable. *Toxicity and exposure data:*
                     Potential health effects of exposure to this substitute include drowsiness or dizziness. The substitute may also irritate the skin or eyes. The substitute could cause asphyxiation if air is displaced by vapors in a confined space. These potential health effects are common to many aerosol solvents. The manufacturer recommends an acceptable exposure limit (AEL) for the workplace of 250 ppm on an 8-hr TWA for HCFO-1233yd(Z). EPA anticipates that users will be able to meet the manufacturer's AEL and address potential health risks by following requirements and recommendations in the manufacturer's SDS, and other safety precautions common to the aerosol industry. *Comparison to other substitutes in this end-use:*
                     HCFO-1233yd(Z) has an ODP of less than 0.00003, comparable to or less than other listed substitutes in this end-use with ODPs ranging from zero to 0.033. HCFO-1233yd(Z)'s GWP of less than one is lower than that of other acceptable substitutes such as HFE-7200, HFE-347mcc3, HFC-365mfc and HFC-4310mee with GWPs ranging from 59 to 1,640. HCFO-1233yd(Z)'s GWP is lower than or comparable to the GWPs of other acceptable substitutes for aerosol solvents, including acetone, methoxytridecafluoroheptene isomers (MPHE), and 
                    *trans*
                    -1-chloro-3,3,3-trifluoroprop-1-ene with GWPs ranging from less than one to seven. Some acceptable substitutes in this end-use are VOC, like HCFO-1233yd(Z), while others are excluded from the definition of VOC. Flammability and toxicity risks 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 manufacturer's AEL, industry standards, recommendations in the manufacturer's SDS, and other safety precautions common in the aerosol industry. EPA finds HCFO-1233yd(Z) acceptable in the aerosol solvent end-use because it does not pose greater overall environmental and human health risk than other available substitutes in the same end-use. D. Cleaning Solvents 1. HCFO-1233yd(Z) *EPA's decision: EPA finds HCFO-1233yd(Z) acceptable as a substitute for use in:* Electronics cleaning
                Metals cleaning
                Precision cleaning HCFO-1233yd(Z) is also known as 
                    *(Z)-*
                    1-chloro-2,3,3-trifluoropropene (CAS Reg. No. 1263679-68-0). You may find a copy of the applicant's submission, with CBI redacted, providing the required health and environmental information for this substitute in this end-use in Docket EPA-HQ-OAR-2003-0118 at 
                    *www.regulations.gov*
                     under the name, “Supporting Materials for Notice 37 Listing of HCFO-1233yd(Z) in Cleaning Solvents, Aerosol Solvents, and Coatings. SNAP Submission Received March 12, 2019.” EPA performed an assessment to examine the health and environmental risks of this substitute. This assessment is available in Docket EPA-HQ-OAR-2003-0118: “Risk Screen on Substitutes in Electronics Cleaning, Metals Cleaning, and Precision Cleaning. Substitute: HCFO-1233yd(Z).” *Environmental information:*
                     The environmental information for this substitute is set forth in the “Environmental information” section in listing in I.C.1. above. *Flammability information:*
                     HCFO-1233yd(Z) is not flammable. *Toxicity and exposure data:*
                     The toxicity information for this substitute is set forth in the “Toxicity and exposure data” section in listing I.C.1. above. *Comparison to other substitutes in these end-uses:*
                     HCFO-1233yd(Z) has an ODP of less than 0.00003, comparable to or less than other listed substitutes in the metals cleaning, electronics cleaning, and precision cleaning end-uses with ODPs ranging from zero to 0.033. HCFO-1233yd(Z)'s GWP of less than 1 is lower than that of other acceptable substitutes such as HFE-7200, HFE-7100, HFC-365mfc and HFC-4310mee with GWPs ranging from 59 to 1,640. HCFO-1233yd(Z)'s GWP is lower than or comparable to the GWPs of other acceptable substitutes for cleaning solvents, including acetone, MPHE, and 
                    ( print page 3043)
                    *trans*
                    -1-chloro-3,3,3-trifluoroprop-1-ene with GWPs ranging from less than one to seven. Some acceptable substitutes in these end-uses are VOC, like HCFO-1233yd(Z), while others are excluded from the definition of VOC. Flammability and toxicity risks 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 manufacturer's AEL, recommendations in the manufacturer's SDS, and other safety precautions common in the cleaning solvents industry. EPA finds HCFO-1233yd(Z) acceptable in the end-uses listed above because it does not pose greater overall environmental and human health risk than other available substitutes in the same end-uses. E. Adhesives, Coatings, and Inks 1. HCFO-1233yd(Z) *EPA's decision: EPA finds HCFO-1233yd(Z) acceptable as a substitute for use as a carrier solvent in:* Coatings HCFO-1233yd(Z) is also known as 
                    *(Z)-*
                    1-chloro-2,3,3-trifluoropropene (CAS Reg. No. 1263679-68-0). You may find a copy of the applicant's submission, with CBI redacted, providing the required health and environmental information for this substitute in this end-use in Docket EPA-HQ-OAR-2003-0118 at 
                    *www.regulations.gov*
                     under the name, “Supporting Materials for Notice 37 Listing of HCFO-1233yd(Z) in Cleaning Solvents, Aerosol Solvents, and Coatings. SNAP Submission Received March 12, 2019.” EPA performed an assessment to examine the health and environmental risks of this substitute. This assessment is available in Docket EPA-HQ-OAR-2003-0118: “Risk Screen on Substitutes in Coatings. Substitute: HCFO-1233yd(Z).” *Environmental information:*
                     The environmental information for this substitute is set forth in the “Environmental information” section in listing I.C.1., above. *Flammability information:*
                     HCFO-1233yd(Z) is not flammable. *Toxicity and exposure data:*
                     The toxicity information for this substitute is set forth in the “Toxicity and exposure data” section in listing I.C.1., above. *Comparison to other substitutes in these end-uses:*
                     HCFO-1233yd(Z) has an ODP of less than 0.00003, comparable to or less than other listed substitutes in this end-use with ODPs ranging from zero to 0.00034. For coatings, HCFO-1233yd(Z)'s GWP of less than one is lower than that of other acceptable substitutes such as HFE-7200 and HFE-7100 with GWPs ranging from 59 to 297. HCFO-1233yd(Z)'s GWP is lower than or comparable to the GWPs of other acceptable substitutes for coatings, including acetone, MPHE, and 
                    *trans*
                    -1-chloro-3,3,3-trifluoroprop-1-ene with GWPs ranging from less than one to seven. Some acceptable substitutes in this end-use are VOC, like HCFO-1233yd(Z), while others are excluded from the definition of VOC. Flammability and toxicity risks 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 manufacturer's AEL, recommendations in the manufacturer's SDS, and other safety precautions common in the coatings industry. EPA finds HCFO-1233yd(Z) acceptable in the coatings end-use because it does not pose greater overall environmental and human health risk than other available substitutes in the same end-use. List of Subjects in 40 CFR Part 82 Environmental protection
Administrative practice and procedure
Air pollution control
Reporting and recordkeeping requirements
 Hans Christopher Grundler, Director, Office of Atmospheric Programs.
 Appendix A: Summary of Decisions for New Acceptable Substitutes Refrigeration and Air Conditioning
End-use
Substitute
Decision
Further information 1Cold Storage Warehouses (
                            *new equipment only*)
HCFO-1233zd(E)
Acceptable
HCFO-1233zd(E) is also known as 
                            *trans*
                            -1-chloro-3,3,3-trifluoroprop-1-ene (Chemical Abstracts Service Registry Number [CAS Reg. No.] 102687-65-0).
                             HCFO-1233zd(E) has an ozone depletion potential (ODP) of less than 0.0004 and a 100-year integrated global warming potential (GWP) of about 3.7. 
                             HCFO-1233zd(E) is nonflammable. 
                             The Workplace Environmental Exposure Limits (WEEL) committee of the Occupational Alliance for Risk Science (OARS) has established a WEEL of 800 ppm as an eight-hour time-weighted average (8-hr TWA) for HCFO-1233zd(E).Ice Skating Rinks (
                            *new equipment only*)
HCFO-1233zd(E)
Acceptable
HCFO-1233zd(E) is also known as 
                            *trans*
                            -1-chloro-3,3,3-trifluoroprop-1-ene (CAS Reg. No. 102687-65-0).
                             HCFO-1233zd(E) has an ODP of less than 0.0004 and a GWP of about 3.7. 
                             HCFO-1233zd(E) is nonflammable. 
                             OARS has established a WEEL of 800 ppm on an 8-hr TWA for HCFO-1233zd(E).Industrial Process Air Conditioning (
                            *new equipment only*)
HCFO-1233zd(E)
Acceptable
HCFO-1233zd(E) is also known as 
                            *trans*
                            -1-chloro-3,3,3-trifluoroprop-1-ene (CAS Reg. No. 102687-65-0).
                             HCFO-1233zd(E) has an ODP of less than 0.0004 and a GWP of about 3.7. 
                             HCFO-1233zd(E) is nonflammable. 
                             OARS has established a WEEL of 800 ppm on an 8-hr TWA for HCFO-1233zd(E).1
                         See recommendations in the manufacturer's SDS and guidance for all listed refrigerants.
 Foam Blowing Agents
End-use
Substitute
Decision
Further information 1Extruded Polystyrene: Boardstock and Billet
Blends of 10 to 90 percent HFO-1234ze(E) by weight and the remainder HCFO-1233zd(E)
Acceptable
This substitute is blends of 10 to 90 percent HFO-1234ze(E) by weight and the remainder HCFO-1233zd(E). HFO-1234ze(E) is also called 1,3,3,3-tetrafluoropropene(E), or 
                            *trans-*
                            1,3,3,3-tetrafluoropropene (Chemical Abstracts Service Registry Number [CAS Reg. No.] 29118-24-9). HCFO-1233zd(E) is also called 
                            *trans*
                            -1-chloro-3,3,3-trifluoro-prop-1-ene (CAS Reg. No. 102687-65-0).( print page 3044)HFO-1234ze(E) has a 100-year integrated global warming potential (GWP) of less than one.
                             HCFO-1233zd(E) has an ozone depletion potential (ODP) of less than 0.0004 and a GWP of 3.7. The blends have an ODP ranging from less than 0.0004 to less than 0.00004 and range in GWP from about 1.3 to about 3.4.HFO-1234ze(E) is not flammable at standard temperature and pressure, however, however, at higher temperatures, such as the temperatures typical for extruding extruded polystyrene: boardstock and billet (XPS), HFO-1234ze(E) may be flammable, particularly at higher humidity levels. HCFO-1233zd(E) is non-flammable.The American Industrial Hygiene Association (AIHA) has established a Workplace Environmental Exposure Limit (WEEL) of 800 ppm as an eight-hour time-weighted average (8-hr TWA) for HFO-1234ze(E), and the Occupational Alliance for Risk Sciences (OARS) has established a WEEL of 800 ppm as an 8-hr TWA for HCFO-1233zd(E).Extruded Polystyrene: Boardstock and Billet
Blends of 10 to 90 percent HFO-1234ze(E) by weight and the remainder HFC-152a
Acceptable
This substitute is blends of 10 to 90 Percent HFO-1234ze(E) by weight and the remainder HFC-152a. HFO-1234ze(E) is also called 1,3,3,3-tetrafluoropropene (E), or 
                            *trans*
                            -1,3,3,3-tetrafluoropropene (CAS Reg. No. 29118-24-9). HFC-152a is also called 1,1-difluoroethane (CAS Reg. No. 75-37-6).
                             The blend and its components have an ODP of zero. HFO-1234ze(E) has a GWP of less than one and HFC-152a has a GWP of 124. The blends range in GWP from about 13 to about 112.HFO-1234ze(E) is not flammable at standard temperature and pressure, however, at higher temperatures, such as the temperatures typical for extruding XPS, HFO-1234ze(E) may be flammable, particularly at higher humidity levels. HFC-152a is flammable at standard temperature and pressure.The AIHA has established a WEEL of 1,000 ppm for HFC-152a and a WEEL of 800 ppm for HFO-1234ze(E), both as an 8-hr TWA.Extruded Polystyrene: Boardstock and Billet
Blends of 0-100% HFO-1234ze(E), 0-70% Methyl Formate, 0-60% HFC-152a, 0-60% CO
                            2
                             and 0-60% Water
Acceptable
This substitute is blends of 0-100% HFO-1234ze(E), 0-70% methyl formate, 0-60% HFC-152a, 0-60% CO
                            2
                             and 0-60% water. HFO-1234ze(E) is also called 1,3,3,3-tetrafluoropropene (E), or 
                            *trans*
                            -1,3,3,3-tetrafluoropropene (CAS Reg. No. 29118-24-9). Methyl formate is also called methyl methanoate or formic acid, methyl ester (CAS Reg. No. 107-31-3). HFC-152a is also called 1,1-difluoroethane, has CAS Reg. No. 75-37-6. CO
                            2
                             has CAS Reg. No. 124-38-9, and water has CAS Reg. No. 7732-18-5.HFO-1234ze(E) and water have GWPs of less than one, CO
                            2
                             has a GWP of one, methyl formate has a GWP of 11, and HFC-152a has a GWP of 124. The blends range in GWP from approximately one to 80.HFO-1234ze(E) is not flammable at standard temperature and pressure; however, at higher temperatures, such as the temperatures typical for extruding XPS, HFO-1234ze(E) may be flammable, particularly at higher humidity levels. HFC-152a and methyl formate are flammable at standard temperature and pressure.The AIHA has established a WEEL of 1,000 ppm for HFC-152a and a WEEL of 800 ppm for HFO-1234ze(E), both as an 8-hr TWA.1
                         See recommendations in the manufacturer's SDS and guidance for all listed foam blowing agents.
 Cleaning Solvents
End-use
Substitute
Decision
Further information 1Electronics cleaning, metals cleaning, precision cleaning
HCFO-1233yd(Z)
Acceptable
HCFO-1233yd(Z) is also known as (Z)-1-chloro-2,3,3-trifluoropropene (CAS Reg. No. 1263679-68-0).
                             HCFO-1233yd(Z) has an ozone depletion potential (ODP) of 0.00003 and a global warming potential (GWP) of less than 1. 
                             This compound is nonflammable.The manufacturer recommends an acceptable exposure limit (AEL) for the workplace for HCFO-1233yd(Z) of 250 ppm on an eight-hour time-weighted average (8-hr TWA).This substitute is subject to a Toxic Substances Control Act (TSCA) section 5(a)(2) Significant New Use Rule (SNUR).1
                         See recommendations in the manufacturer's SDS and guidance for all listed cleaning solvents.
 Aerosols
End-use
Substitute
Decision
Further information 1Aerosol solvents
HCFO-1233yd(Z)
Acceptable
HCFO-1233yd(Z) is also known as (Z)-1-chloro-2,3,3-trifluoropropene (CAS Reg. No. 1263679-68-0).
                             HCFO-1233yd(Z) has an ozone depleting potential (ODP) of 0.00003 and a global warming potential (GWP) of less than 1. 
                             This compound is nonflammable.The manufacturer recommends an acceptable exposure limit (AEL) for the workplace for HCFO-1233yd(Z) of 250 ppm on an eight-hour time-weighted average (8-hr TWA).This substitute is subject to a Toxic Substances Control Act (TSCA) section 5(a)(2) Significant New Use Rule (SNUR).1
                         See recommendations in the manufacturer's SDS and guidance for all listed aerosols.
 
 
 Adhesives, Coatings, and Inks
End-use
Substitute
Decision
Further information 1Coatings
HCFO-1233yd(Z)
Acceptable
HCFO-1233yd(Z) is also known as (Z)-1-chloro-2,3,3-trifluoropropene (CAS Reg. No. 1263679-68-0).HCFO-1233yd(Z) has an ozone depleting potential (ODP) of 0.00003 and a global warming potential (GWP) of less than 1.This compound is nonflammable.The manufacturer recommends an acceptable exposure limit (AEL) for the workplace for HCFO-1233yd(Z) of 250 ppm on an eight-hour time-weighted average (8-hr TWA).This substitute is subject to a Toxic Substance Control Act (TSCA) section 5(a)(2) Significant New Use Rule (SNUR).1
                         See recommendations in the manufacturer's SDS and guidance for all listed carrier solvents for adhesives, coatings, and inks.


# Footnotes

1.
    
                         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. Back to Citation
 2.
    
                         Unless otherwise stated, all GWPs in this document for individual chemicals are 100-year values from: 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. This document is accessible at 
                        *www.ipcc.ch/​publications_​and_​data/​ar4/​wg1/​en/​contents.html.*
                         For blends of chemicals, such as R-507A, this document weights the GWPs of each component of the blend by their mass percentage in the blend, based upon the 100-year GWPs in IPCC, 2007, if available in that document. Back to Citation
 3.
    
                         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.*
                         (WMO, 2018) Back to Citation
 4.
    
                         WMO, 2018. Back to Citation
 5.
    
                         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.* Back to Citation
 6.
    
                         That is, alkanes with three to six carbons such as butane, n-pentane, isopentane, and cyclopentane. Back to Citation
 7.
    
                         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. Back to Citation
 8.
    
                         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.* Back to Citation
 9.
    
                         Ibid. Back to Citation
 10.
    
                         Ibid. Back to Citation
 11.
    
                         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.* Back to Citation
 12.
    
                         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.* Back to Citation
 13.
    
                         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. Back to Citation
 14.
    
                         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.* Back to Citation
 15.
    
                         Ibid. Back to Citation
 16.
    
                         Ibid. Back to Citation
 17.
    
                         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. Back to Citation
 18.
    
                         WMO, 2018. Back to Citation
 19.
    
                         IPCC, 2007. Back to Citation
 20.
    
                         IPCC, 2007. Back to Citation
 21.
    
                         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 × 10−4.
    
                        . “The global warming potential of near-surface emitted water vapour,” Steven C. Sherwood, Vishal Dixit and Chryséis Salomez. 
                        *Environ. Res. Lett.*
                         13 (2018) 104006. Back to Citation
 22.
    
                         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.* Back to Citation
 23.
    
                         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. Back to Citation
 24.
    
                         WMO, 2018. Back to Citation
 25.
    
                         WMO, 2018. Back to Citation
 26.
    
                         WMO, 2018. Back to Citation
 27.
    
                         Kazuaki Tokuhashi, Tadafumi Uchimaru, Kenji Takizawa, and Shigeo Kondo, 2018. Rate Constants for the Reactions of OH Radical with the (E)/(Z) Isomers of CF3
                        CF=CHCl and CHF2
                        CF=CHCl (
                        *J.Phys. Chem. A*
                         2018, 122, 3120-3127) (Tokuhashi et al., 2018). Back to Citation


[FR Doc. 2022-00998 Filed 1-19-22; 8:45 am] BILLING CODE 6560-50-P