Per- and Polyfluoroalkyl Substances (PFAS)

HFCs, HFOs and HCFOs are a distinct subset and due to their properties are not commonly regarded as PFAS.

Per- and polyfluoroalkyl substances (“PFAS”) covers a broad range of substances that according to currently accepted terminology contain at least one perfluoralkyl group. HFCs, HFOs and HCFOs are not commonly regarded as PFAS. They break down in the atmosphere to substances that naturally occur in the environment. They have a defined atmospheric lifetime, measured in days or months for HFOs and HCFOs, and years or decades for HFCs.

More than 4700 individual substances have been catalogued as PFAS by the OECD [1] and the Inter-Organization Programme for the sound Management of Chemicals (IOMC), and these substances have a wide range of very different (eco)toxicological and physical properties. The catalogue lists those PFASs, including perfluorocarbons, that contain a perfluoroalkyl group with three or more carbons (i.e. –CnF2n–, n ≥ 3) [2]. It is important to highlight that the HFCs, HFOs and HCFOs, used in the refrigeration,air-conditioning and insulation foam industries do not have this group and are not individual substances listed in the OECD catalogue.

See EFCTC Position Paper: Per- and Polyfluoroalkyl Substances: HFCs and HFOs a distinct subset (March 2020)

Why are some PFASs a particular concern to the EU?

Since the late 1990s and early 2000s, numerous studies have been conducted to understand and assess PFAS, with a particular focus on so-called “long-chain” perfluoroalkyl acids (PFAAs)3 and their precursors. The EU has established regulations that restrict some types of long-chain PFAAs called PFOS and PFOA and their salts and related compounds4. The EU has determined that both meet the criteria to be classified as persistent, bioaccumulative and toxic substances”(‘PBT’)5.

HFCs, HFOs and HCFOs are different!

The HFCs, HFOs and HCFOs are short chain substances (≤ C5 chains) and do not meet the criteria to be classified as persistent, bioaccumulative and toxic substances (‘PBT’). They do not meet the criteria to be considered persistent as defined in REACH Regulation Annex XIII.  They are gases, or low boiling point liquids, and when released to the environment, due to the absence of relevant functional groups such as acidic groups,  will enter almost exclusively into the ambient air and have little tendency to partition to the hydrosphere, biota, sediment or soil [6]. They have low potential for adsorption (low log Kow ) and are expected to rapidly volatilise to the atmosphere.

An extensive body of research is available concerning their environmental fate. They are not stable in the atmosphere and they simply cannot breakdown to long chain PFAS substances. Their breakdown mechanisms in the atmosphere are generally known (see table for detailed breakdown products and source references which is available here). Their final degradation products are all substances that are believed to have occurred naturally in the environment for millions of years.

Why HFCs, HFC/HFO blends HFOs and HCFOs have an important role?

Improvements in energy efficiency in refrigeration and air-conditioning equipment during the transition to low-GWP refrigerants will further increase the climate benefits of the HFC phasedown under the F-Gas Regulation and the Kigali Amendment.
Widely used for heat pumps and required for the widespread adoption of ORC (Organic Rankine Cycle) and high temperature heat pump systems used for energy recovery from a wide range of waste heat sources.
Highly trained engineers use their knowledge and expertise to handle HFCs, HFOs and HCFOs in order to prevent their emissions and for recycling and re-use. In the context of the Green Deal and decarbonisation, HFCs, HCFOs and HFOs are part of the solution.

Regulatory Management Option Assessment of the group of PFAS

Recently, five European countries [7] have taken the initiative to prepare a Regulatory Management Option Assessment [8] of the group of PFAS, with a significantly expanded substance scope, as a first step in the development of proposals for possible restrictions under the EU REACH Regulation based on persistent/very Persistent criteria according to REACH Annex XIII and that are not able to degrade under environmental conditions [9]. This significantly expanded scope could increase the number of potentially included substances to over 10,000 and includes HFCs, HFOs and HCFOs that are not commonly regarded as  PFAS.  Stakeholders were invited to submit evidence on this expanded group.

In its response to the call for evidence, EFCTC commented that while HFCs, HFOs and HCFOs are covered by the definition of PFAS used for this survey, they do not exhibit the properties of the group of substances that are more commonly considered as PFAS (longer chain organic highly fluorinated substances with a C6 core or higher) nor would their atmospheric breakdown products commonly be considered PFAS.  As demonstrated in the EFCTC submission, the HFCs and HFOs substances do not meet the criteria for persistency as set out in REACH Regulation Annex XIII.

EFCTC takes the view that any consideration of regulatory assessment should be at a subset or individual substance level and not at the PFAS group level and should be based on sound scientific evidence that takes into account specific structures and properties. Consequently, EFCTC concluded that it would make sense to exclude this group of substances from the broad scope of this Regulatory Management Option Assessment.

All the breakdown products of HFCs, HFOs and HCFOs are natural substances

HFCs, HFOs and HCFOs degrade in the environment to natural substances. The mechanisms and final degradation products are generally known. Carbon-fluorine bonds are in fact broken as the substances degrade. The final degradation products are all substances that are believed to have occurred naturally in the environment for millions of years. 

One of the naturally occurring breakdown products from some HFCs and HFOs is trifluoroacetic acid (TFA). The OECD report [1] notes that “According to the currently most accepted terminology (Buck et al., 2011), per- and polyfluoroalkyl substances (PFASs) are a family of anthropogenic chemicals….” In contrast, TFA occurs naturally which makes it unique and distinct. It is well established that TFA is a ubiquitous natural component of the hydrosphere [10]. The oceans, both coastal and deep-ocean seawater, contain over 200 million tonnes of TFA [11, 12], having accumulated over many million years from chemical reactions in or around sub-sea volcanic vents.

While TFA is produced as a breakdown product of some HFCs and some HFOs (see table for detailed breakdown products and source references which is available here) it is widely dispersed at very low concentrations,  is rained out and transported to the oceans by river systems,  does not bioconcentrate in aquatic organisms and does not biomagnify in the food chain [13].

The large body of published field measurements, toxicological studies, modelling studies, and environmental assessments point to a clear conclusion: The current and estimated future concentrations of TFA and its salts resulting from degradation of HCFCs, HFCs, and HFOs do not pose any known risk to human or ecosystem health [10, 11]. 

Latest News:

PFAS call for evidence: EFCTC submits comprehensive information package about HFCs and HFOs,  read the news item from the September 2020 news here.  

Sources:

[1] May 4, 2018 published report Toward a New Comprehensive Global Database of Per and Polyfluoroalkyl Substances (PFASs): Summary Report on Updating the OECD 2007 List of Per and Polyfluoralkyl Substances (PFASs), Series on Risk Management No. 39  http://www.oecd.org/officialdocuments/publicdisplaydocumentpdf/?cote=ENV-JM-MONO(2018)7&doclanguage=en &  https://www.oecd.org/chemicalsafety/risk-management/global-database-of-per-and-polyfluoroalkyl-substances.xlsx

[2] In addition, the OECD catalogue covers fluorinated ethers with –CnF2nOCmF2m−, n and m ≥ 1, which are not relevant to HFCS, HFOs and HCFOs

[3] For example PFOA perfluorooctanoic acid CF3CF2CF2CF2CF2CF2CF2COOH

[4] PFOA, its salts and PFOA-related compounds are listed in Annex XVII of the REACH Regulation (EC) No 1907/2006 subject to certain derogations. It is also subject to Regulation 2020/784 amending Annex I to Regulation (EU) 2019/1021 of the European Parliament and of the Council as regards the listing of perfluorooctanoic acid (PFOA), its salts and PFOA-related compounds. Regulation 2019/1021 on persistent organic pollutants lists perfluorooctane sulfonic acid and its derivatives (PFOS) C8F17SO2X (X = OH, Metal salt (O-M+), halide, amide, and other derivatives including polymers). PFOS was originally included in REACH annex xvii restricted substances list. After PFOS was added to the Annex B of the Stockholm Convention in 2009, the European Commission removed PFOS from REACH annex xvii and added it to the annex I of the Regulation (EC) No 850/2004 of the European Parliament and of the Council on persistent organic pollutants. PFOS is now regulated as a persistent organic pollutant (POP) in EU.

[5] REACH Regulation 1907/2006 Annex XIII Criteria for the identification of persistent, bioaccumulative and toxic substances, and very persistent and very bioaccumulative substances.

[6] Classification and labelling for each substance can be accessed from https://www.fluorocarbons.org/wp-content/uploads/2020/07/2020_07_27_Fluorocarbons-links-to-ECHA-substance-infocards-2020-July.pdf

[7] Denmark, Germany, Norway, Sweden, The Netherlands see https://echa.europa.eu/sv/-/five-european-states-call-for-evidence-on-broad-pfas-restriction

[8] For general information about RMOA see https://echa.europa.eu/sv/understandng-rmoa

[9] See  https://echa.europa.eu/rmoa/-/dislist/details/0b0236e184db2d36

[10] World Meteorological Organization Global Ozone Research and Monitoring Project—Report No. 58 SCIENTIFIC ASSESSMENT OF OZONE DEPLETION: 2018 Information for Policymakers Chapter 6 page 6.13

[11] Solomon, K.R., Velders, G.J., Wilson, S.R., Madronich, S., Longstreth, J., Aucamp, P.J., Bornman, J.F. (2016): Sources, fates, toxicity, and risks of trifluoroacetic acid and its salts: Relevance to substances regulated under the Montreal and Kyoto Protocols. Journal of Toxicology and Environmental Health Part B, 19, pp 289-304 doi:1080/10937404.2016.1175981, 2016

[12] World Meteorological Organization Global Ozone Research and Monitoring Project—Report No. 58 SCIENTIFIC ASSESSMENT OF OZONE DEPLETION: 2018 Information for Policymakers Chapter 6 page 6.14

[13] UNEP Ozone Secretariat June 2015. Ecological Issues on the feasibility of managing HFCs: Focus on TFA Inter-sessional informal meeting, 12-13 June 2015