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Federal Register / Vol. 86, No. 86 / Thursday, May 6, 2021 / Rules and Regulations
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whenever the initial risk screen indicated a potential risk, the substitute was evaluated further to ascertain whether the potential risk was accurately estimated and if management controls could reduce any risk to acceptable levels. In this case, in the worst-case scenario where the 25% RCL
was exceeded, we concluded that the additional risk mitigation offered by the UL Standard and our other use conditions adequately addressed any such risk.
ii. Toxicity and PFAS
Comment: EIA indicated there are concerns regarding potential risks to human health and the environment due to toxicity of trifluoroacetic acid TFA
and other by-products of breakdown of HFO1234yf, which is a component of the five refrigerant blends. They pointed to scientific literature that finds HFO1234yf has a 100% conversion rate into TFA. They noted that increased use of alternative refrigerants including HFOs has increased ecosystem levels of anthropogenic TFA. EIA advised EPA to lead with caution but did not, however, recommend that additional restrictions be placed on these refrigerant blends based on TFA concerns. NRDC noted that EPAs risk analyses do not evaluate the potential human health and environmental impacts of approving additional uses for substances known to degrade into TFA. NRDC pointed to the previous analyses EPA performed on TFA and requested that EPA revise those studies to include the potential use of the five blends in the airconditioning sector.
Response: EPA does not agree that increased controls on HFOs or other refrigerants is warranted to address generation of TFA. EPA studied the potential generation of TFA when we first listed neat i.e., 100%, not in blends HFO1234yf as acceptable subject to use conditions in motor vehicle air conditioners. The myriad studies we referenced all concluded that the additional TFA from HFO1234yf did not pose a significant additional risk, even if it were assumed to be used as the only refrigerant in all refrigeration and air conditioning equipment 76 FR
1749217493, March 29, 2011. More recently, the World Meteorological Organization WMO concluded that there is increased confidence that TFA produced from degradation of HFCs, HCFCs, and HFOs will not harm the environment over the next few decades while also calling for periodic reevaluation of this conclusion.35 EPA
35 World Meteorological Organization WMO, Executive Summary: Scientific Assessment of
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likewise finds that the data on TFA is not sufficient to propose or establish additional restrictions under SNAP at this time. We further note that the venting prohibition under section 608c of the CAA, codified at 40 CFR
82.154a, and accompanying refrigerant management requirements reduce emissions of these refrigerants. EPA
intends to continue reviewing the research on potential impacts from TFA
in the future.
Comment: NRDC asked EPA to revise the Agencys analysis of the substances included in this rulemaking that are polyfluoroalkyl or perfluoroalkyl substances PFAS, citing two recent papers on the subject.36 37
Response: EPA acknowledges these references. Upon review of these papers, EPA does not conclude that any revisions to the evaluation of overall risk to human health and the environment of the refrigerants addressed in this final rule is necessary at this time. While the papers NRDC
referenced indicate there are potential health effects due to accumulation of PFAS in the environment, they do not provide information concerning the incremental effect that adoption of the five refrigerants listed in this rule for the residential and light commercial air conditioning end-use would have or how those effects would compare to effects from other available substitutes in this end-use.
Both papers reference decision IV/25
by parties to the Montreal Protocol on Substances that Deplete the Ozone Layer. That decision concerns applying specific criteria and procedures in assessing an essential use for the purposes of the control measures in Article 2 of the Protocol and therefore is not directly relevant to the SNAP
program. Cousins et al. reviewed several examples of PFAS uses to assess whether they would consider those uses to be essential, and those uses did not include the refrigerants considered in this final rule. Kwiatkowski et al.
likewise did not provide an overview of refrigerants to indicate any additional Ozone Depletion: 2018, World Meteorological Organization, Global Ozone Research and Monitoring ProjectReport No. 58, 67 pp., Geneva, Switzerland, 2018. Available at https
ozone.unep.org/sites/default/files/2019-04/SAP2018-Assessment-report-ES-rev%20%281%29.pdf.
36 Cousins, Ian T, et al. The concept of essential use for determining when uses of PFASs can be phased out. Environmental Science: Processes &
Impacts. The Royal Society of Chemistry. May 28, 2019. https pubs.rsc.org/en/content/
articlelanding/2019/em/c9em00163h!divAbstract.
37 Kwiatkowski, Carol F. et al. Scientific Basis for Managing PFAS as a Chemical Class.
Environmental Science & Technology Letters. June 30, 2020. https pubs.acs.org/doi/10.1021/
acs.estlett.0c00255.

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restrictions that they would consider warranted.
EPA intends to continue monitoring the scientific research on PFAS in the future and consider whether this information is relevant for the SNAP
program.
e. Training Comment: ACCA argues that training and certification of technicians on the handling of A2L refrigerants is necessary for safety and consumer peace of mind. ACCA indicated it and others were developing training and guidelines on A2L refrigerants and provided a list of several aspects that they are addressing. Carrier noted that industry has developed an exam for flammable refrigerants under the North American Technician Excellence NATE
certification organization. Chemours also pointed to NATE and ACCA
training as well as that by the Refrigeration Service Engineers Society RSES, AHRI, and that provided by refrigerant producers and equipment manufacturers. Daikin also noted that AHRI is developing guidelines for A2L
refrigerants and that equipment manufacturers are providing training to their service personnel. Chemours stated that technician training, guidelines, informational brochures, and certifications for flammable refrigerants have been or are currently being developed by a number of industry organizations and that recovery machines, leak detectors, service cylinders and fittings are also available to the industry. HARDI
indicated the industry is supporting the development of training to allow contractors to install newly designed equipment. ACCA asked EPA to work with them and other industry stakeholders to develop and implement training standards for the handling of flammable refrigerants.
Carrier similarly encouraged industry stakeholder engagement and Chemours stated that given the number of programs that already exist, EPA should collect a wide range of comments and move forward with a separate rule on training that incorporates stakeholder feedback. Rheem agreed that EPA
should not undertake the creation of new training requirements in this rule and went further to say they were not in favor of a separate rulemaking, believing industry should create any new training requirements.
Response: EPA acknowledges the commenters information related to their work to educate and train technicians on the proper and safe use of flammable refrigerants, including the A2L
refrigerants in this final rule. In the
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