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ZDHC Guidance Sheet
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PER–FLUOROALKYL AND POLY-FLUOROALKYL SUBSTANCES (PFAS)

Background

Per- and poly-fluoroalkyl substances (PFAS) are a broad class of thousands of man-made synthetic fluorinated chemicals used in various industries and consumer goods since the 1940s. PFAS do not occur naturally in the environment. The strong carbon-fluorine bonds present in this chemistry prevents them from degradation during usage and in the environment and hence they are known as “forever chemicals”. PFAS are also easily transmitted in the environment across great distances from their point of release and some are hence included as Persistent Organic Pollutants (POP) under the Stockholm Convention.

Due to their extensive use, ability to migrate and persistence, they can be found in low concentrations in a range of food items as well as in the environment and in the blood of humans and other animals worldwide 1, 2

Uses in textile & footwear supply chains3, 4

  • Durable oil and water repellant functional finishes
  • Soil release functional finishes
  • Mold release (injection molding process)
  • Low friction treatments (Polishes, Lubricants, Waxes and Greases)
  • Surfactant in softeners, defoamers, foam stabilizers, surface cleaning agents, coatings, digital printing, high-bond glues
  • Emulsifier in liquid suspensions – Dyestuff, textile finishing agents

Harmful effects of PFAS2, 5, 7

(All these effects are not caused by every individual PFAS, but certain health and environmental hazards such as persistence are common properties of these substances)

  • Very Persistent, very Bioaccumulative (vPvB)
  • Reprotoxic; capable of reducing fertility, damage to growth of foetuses or elevated blood pressure in pregnant women
  • Associated with human cancers including prostate, kidney, and testicular cancers
  • May potentially affect the human endocrine (hormonal) system
  • Increased risk of obesity and/or high cholesterol, which can harm the liver
  • Reduced capacity of the immune system to combat infections
  • Developmental impacts in children such as low birth weight, premature puberty, bone abnormalities or behavioural alterations
  • May have long term adverse impacts on aquatic environments

Chemistry and Terminology

The term PFAS refers to fluorinated substances that have at least one fully fluorinated methyl (-CF3 ) or methylene (-CF2-) carbon atom (without any H/Cl/Br/I atom attached to it). 8 The chemistry is further divided into two types: 5

Polymer PFAS

where the Fluorine atoms are directly bonded to the carbon-only polymer backbone or a carbon-oxygen polymer backbone or where fluorinated side-chains branch out from the carbon polymer backbone. Fluoropolymers (like PTFE, ETFE) and fluorinated polymers (like fluorinated urethane polymers) that are used for repellent functional finishes in the textile and leather supply chain are examples of polymer PFAS.

Non-polymer PFAS

All hydrogen atoms on all carbon atoms in the alkyl chain attached to a functional group have been replaced with fluorine (per fluoroalkyl substances)

Examples:

  • Perfluoroalkyl carboxylic acids (PFCA), such as per fluoro octanoic acid (PFOA)
  • Per fluoroalkane sulfonic acids (PFSA), such as per fluoro octane sulphonate (PFOS) These are further sub-divided into:
  • Long chain PFCA - 8 or more carbon atoms (7 or more carbons are perfluorinated)
  • Long chain PFSA - 6 or more carbon atoms (6 or more carbons are perfluorinated)
  • Short chain PFCA - 7 or fewer carbon atoms (6 or fewer carbons are perfluorinated)
  • Short chain PFSA - 5 or fewer carbon atoms (5 or fewer carbons are perfluorinated) ii. All hydrogen atoms on at least one but not all carbon atoms have been replaced with fluorine (poly fluoroalkyl substances) Examples: Fluorotelomer alcohols (FTOH), fluorotelomer carboxylic acids (FTCA)

Safer alternatives to fluorinated repellent functional finishes in the textile and footwear supply chain:

The chemical industry has worked on a number of fluorine-free substitutes due to the harmful concerns of PFAS. These chemical products can only impart the durable water repellancy and not oil repellancy. These formulations are based on following chemistries: 4, 9

  • Paraffin
  • Stearic acid-melamine
  • Silicone
  • Polyurethane
  • Dendrimer
  • Poly acrylates

The OECD offers some information on PFAS alternatives based on country-specific studies for alternatives, however they are not supported by the entire group of companies. 3, 10 Any alternative selected must be carefully vetted to ensure a regrettable substitution is not made. Also, the chosen alternative must be conformant to the latest version of the ZDHC MRSL.

Important Regulations

Many nations across the world have regulations regarding the use of PFAS in products in the form of complete bans or limits. Uniform regulations for these substance class(es) currently exist in Europe in Regulation (EC) No. 1907/2006 REACH (Annex XVII; Candidate List) and Regulation (EU) 2019/1021 (POP Regulation), among others.11

Some important regulations are listed here for general reference with no intention to be used as a reference for any legal compliance purpose and this information is updated to the issue date of this document: 2, 5

  • The Stockholm Convention regulates the global elimination of PFOS and its derivatives, PFOA, its salts and PFOA-related compounds, PFHxS, its salts and related compounds.
  • In Switzerland, perfluorohexane-1-sulfonic acid, its salts and PFHxS-related compounds were already added to the national law to phase out the use in mixtures/substances and products.
  • In June 2019 and January 2020, two PFAS groups were identified as SVHCs. The SVHC identification was based on their persistence, mobility and toxicity, which were considered to pose a threat to human health and wildlife when exposed through the environment (including through drinking water). These groups are:
    • 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy) propionic acid, its salts and its acyl halides (HFPO-DA), a short-chain PFAS substitute for PFOA in fluoropolymer production
    • perfluorobutane sulfonic acid (PFBS) and its salts, a replacement of PFOS
  • A few PFAS already have a harmonised classification and labelling under the CLP Regulation. These include:
    • perfluorooctanoic acid (PFOA)
    • ammonium pentadecafluorooctanoate (APFO)
    • perfluorononan-1-oic acid (PFNA) and its sodium and ammonium salts
    • nonadecafluorodecanoic acid (PFDA) and its sodium and ammonium salts
  • The revision of the EU Drinking Water Directive, which came into force on January 12th 2021, sets a limit for 20 perfluorinated acids in the range of C4-C13.
  • The Safer Clothes and Textile Act (AB 1817), passed by California in the United States on 30th September 2022, bans the use of PFAS in textiles and textile articles, starting 1st January 2025.12

Relevance to the ZDHC MRSL:

The use of any formulation based on, or including PFAS, is not permitted (for fashion, sport or outdoor clothing and apparel and home textiles) as per the ZDHC MRSL V3.0 published in November 2022.13

PFAS for certain technical textiles

There may be certain critical (technical textile) end uses where legally or contractually mandated standards may only be achieved using PFAS (e.g. military, medical, protective clothing, transportation). Only fluorinated polymers based on C6 telomer chemistry with a minimised content of impurities may be applicated for these essential uses. Nevertheless, the chemical formulations within the chemical inventory of a Supplier will always be deemed ZDHC MRSL non-conformant and the ZDHC Supplier Platform will appraise the end uses of any PFAS within an inventory.

There are thousands of individual substances categorised as PFAS. For confirmatory testing as mentioned in the ZDHC MRSL V3.0, the procedures and substance series should be considered as mentioned in the relevant standards for textile and leather:  EN 17681-1, 2022; EN 17681-2, 2022;  EN ISO 23702-1, 2021; EN ISO 20137, 2022. The below table is for information only about the broad class of PFAS substances.

Table 1 (For information only): Broad class of PFAS14

Perfluoroalkyl Carboxylic Acids and Derivatives - PFCA;

Substance CAS No.
Perfluorocarboxylic acids and its salts Several
Perfluorobutanoic acid and its salts Several
Perfluorobutanoic acid 375-22-4
Perfluorohexanoic acid and its salts Several
Perfluorohexanoic acid (PFHxA) 307-24-4


Perfluoroheptanoic acid and its salts

Substance CAS No.
Perfluoroheptanoic acid 375-85-9
Perfluorooctanoic acid and its salts Several
Perfluorooctanoic acid (PFOA) 335-67-1
Ammonium pentadecafluoro octanoate 3825-26-1
Octanoic acid, 2,2,3,3,4,4,5,5,6,6,7,7,8,8,8- pentadecafluoro-, sodium salt (1:1) 335-95-5
Potassium perfluorooctanoate 2395-00-8
Perfluorononanoic acid and its salts Several
Perfluorononanoic acid 375-95-1
Sodium salts of perfluorononan-1-oic-acid 21049-39-8
Ammonium salts of perfluorononan-1-oic-acid 4149-60-4
Perfluorodecanoic acid and its salts Several
Perfluorodecanoic acid 335-76-2
Ammonium nonadecafluoro-decanoate 3108-42-7
Decanoic acid, nonadecafluoro-, sodium salt 3830-45-3
Perfluoroundecanoic acid and its salts Several
Perfluoroundecanoic acid 2058-94-8
Perfluorododecanoic acid and its salts Several
Perfluorododecanoic acid 307-55-1
Perfluorotridecanoic acid and its salts Several
Perfluorotridecanoic acid 72629-94-8
Perfluorotetradecanoic acid and its salts Several
Perfluorotetradecanoic acid 0376-06-07
Perfluorohexanoic acid related substances Several
Perfluorohexylethyl alcohols Several
Perfluorohexyl-ethanol 647-42-7
Perfluorohexylethyl olefins Several
Perfluorohexylethene 25291-17-2
Perfluorohexylethyl halides Several
Tridecafluoro-1-iodohexane 355-43-1
1H,1H,2H,2H-Perfluorooctyliodide 2043-57-4
Perfluorohexylethyl acrylates or methacrylates Several
Perfluorohexylethyl polymers Several
Perfluorooctanoic acid related substances Several
Methyl perfluorooctanoate 376-27-2
Ethyl perfluorooctanoate 3108-24-5
Perfluorooctylethyl alcohols Several
Perfluorooctylethanol 678-39-7
Perfluorooctylethyl olefins Several
Perfluorooctylethene 21652-58-4
Perfluorooctylethyl halides Several
Heptadecafluoro-1-iodooctane 507-63-1
1H,1H,2H,2H-Perfluorodecyliodide 2043-53-0
Pentadecafluorooctyl fluoride 335-66-0
Perfluorooctylethyl acrylate or methacrylate Several
Perfluorooctylethyl polymers Several
Perfluoroalkyl compounds, branched Several
2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)propionic acid, its salts and its acyl halides Several
2,3,3,3-tetrafluoro-2-(heptafluoro-propoxy) propionic acid 13252-13-6
Potassium 2,3,3,3-tetrafluoro-2-(heptafluoro-propoxy) propionate 67118-55-2
Ammonium 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)propanoate 62037-80-3
2,3,3,3-tetrafluoro-2-(heptafluoro-propoxy) propionyl fluoride 2062-98-8
Perfluoroalkyl Sulfonic Acids and Derivatives - PFSA
Perfluorobutane sulfonic acid and its derivatives Several
Perfluorobutane sulfonic acid and its salts Several
Perfluorobutane sulfonic acid 375-73-5
Perfluorobutane sulfonates 45187-15-3
Perfluorohexane sulfonic acid and its derivatives Several
Perfluorohexane sulphonic acid and its salts Several
Perfluorohexane sulfonic acid 355-46-4
Perfluorohexane sulfonate 108427-53-8
Potassium perfluorohexane-1-sulphonate 3871-99-6
Ammonium perfluorohexane-1-sulphonate 2723-08-05
Tridecafluorohexanesulphonic acid, compound with 2,2'-iminodiethanol (1:1) 70225-16-0
1-Hexanesulfonic acid, 1,1,2,2,3,3,4,4,5,5,6,6,6-tridecafluoro-, lithium salt (1:1) 55120-77-9
1-Hexanesulfonic acid, 1,1,2,2,3,3,4,4,5,5,6,6,6-tridecafluoro-, zinc salt 70136-72-0
1-Hexanesulfonic acid, 1,1,2,2,3,3,4,4,5,5,6,6,6-tridecafluoro-, compd. with N,N-diethylethanamine (1:1) 72033-41-1
1-Hexanesulfonic acid, 1,1,2,2,3,3,4,4,5,5,6,6,6-tridecafluoro-, sodium salt 16846-12-05
Iodonium, bis[(1,1- dimethylethyl)phenyl]-, salt with 1,1,2,2,3,3,4,4,5,5,6,6,6-tridecafluoro-1- hexanesulfonic acid (1:1) (9CI) 866621-50-3
Sulfonium, (4-methylphenyl)diphenyl-, 1,1,2,2,3,3,4,4,5,5,6,6,6-tridecafluoro-1- hexanesulfonate (1:1) 910606-39-2
Sulfonium, [4-[(2-methyl-1-oxo-2- propenyl)oxy]phenyl]diphenyl-, salt with 1,1,2,2,3,3,4,4,5,5,6,6,6-tridecafluoro-1- hexanesulfonic acid (1:1) 911027-69-5
1-Hexanesulfonic acid, 1,1,2,2,3,3,4,4,5,5,6,6,6-tridecafluoro-, cesium salt (1:1) 92011-17-1
1-Butanaminium, N,N,N-tributyl-, salt with1,1,2,2,3,3,4,4,5,5,6,6,6- tridecafluoro-1-hexanesulfonic acid 108427-54-9
Ethanaminium, N,N,N-triethyl-, salt with 1,1,2,2,3,3,4,4,5,5,6,6,6-tridecafluoro-1- hexanesulfonic acid (1:1) 108427-55-0
1-Hexanesulfonic acid, 1,1,2,2,3,3,4,4,5,5,6,6,6-tridecafluoro-, compd. with pyrrolidine (1:1) 1187817-57-7
Beta-Cyclodextrin, compd. with 1,1,2,2,3,3,4,4,5,5,6,6,6-tridecafluoro-1- hexanesulfonic acid ion(1-) (1:1) 1329995-45-0
Gamma-Cyclodextrin, compd. with 1,1,2,2,3,3,4,4,5,5,6,6,6-tridecafluoro-1- hexanesulfonic acid ion(1-) (1:1) 1329995-69-8
Methanaminium, N,N,N-trimethyl-, salt with1,1,2,2,3,3,4,4,5,5,6,6,6- tridecafluoro-1-hexanesulfonic acid (1:1) 189274-31-5
1-Hexanesulfonic acid, 1,1,2,2,3,3,4,4,5,5,6,6,6-tridecafluoro-, compd.with 2-methyl-2-propanamine (1:1) 202189-84-2
1-Hexanesulfonic acid, 1,1,2,2,3,3,4,4,5,5,6,6,6-tridecafluoro-, gallium salt (9CI) 341035-71-0
1-Hexanesulfonic acid, 1,1,2,2,3,3,4,4,5,5,6,6,6-tridecafluoro-, scandium(3+) salt (3:1) 350836-93-0
Sulfonium, tris[4-(1,1- dimethylethyl)phenyl]-, salt with 1,1,2,2,3,3,4,4,5,5,6,6,6-tridecafluoro-1- hexanesulfonic 425670-70-8
Iodonium, bis[4-(1,1- dimethylpropyl)phenyl]-, salt with 1,1,2,2,3,3,4,4,5,5,6,6,6-tridecafluoro-1- hexanesulfonic 421555-74-0
Sulfonium, (thiodi-4,1- phenylene)bis[diphenyl-, salt with 1,1,2,2,3,3,4,4,5,5,6,6,6-tridecafluoro-1- hexanesulfonic 421555-73-9
1-Hexanesulfonic acid, 1,1,2,2,3,3,4,4,5,5,6,6,6-tridecafluoro-, neodymium(3+) salt (3:1) 41184-65-0
1-Hexanesulfonic acid, 1,1,2,2,3,3,4,4,5,5,6,6,6-tridecafluoro-, yttrium(3+) salt (3:1) 41242-12-0
Sulfonium, [4-[(2-methyl-1-oxo-2- propen-1-yl)oxy]phenyl]diphenyl-, 1,1,2,2,3,3,4,4,5,5,6,6,6-tridecafluoro-1- hexanesulfonate (1:1) 911027-68-4
Dibenzo[k,n][1,4,7,10,13]tetraoxathiacy clopentadecinium, 19-[4-(1,1- dimethylethyl)phenyl]-6,7,9,10,12,13- hexahydro-, 1,1,2,2,3,3,4,4,5,5,6,6,6- tridecafluoro-1-hexanesulfonate (1:1) 928049-42-7
Phosphonium, triphenyl(phenylmethyl)-, 1,1,2,2,3,3,4,4,5,5,6,6,6-tridecafluoro-1-hexanesulfonate (1:1) 1000597-52-3
Ethanaminium, N-[4-[[4-(diethylamino)phenyl][4-(ethylamino)-1-naphthalenyl]methylene]-2,5-cyclohexadien-1-ylidene]-N-ethyl-, 1,1,2,2,3,3,4,4,5,5,6,6,6-tridecafluoro-1- hexanesulfonate (1:1) 1310480-24-0
Methanaminium, N-[4-[[4-(dimethylamino)phenyl][4-(ethylamino)-1-naphthalenyl]methylene]-2,5-cyclohexadien-1-ylidene]-N-methyl-, 1,1,2,2,3,3,4,4,5,5,6,6,6-tridecafluoro-1- hexanesulfonate (1:1) 1310480-27-3
Methanaminium, N-[4-[[4-(dimethylamino)phenyl][4-(phenylamino)-1-naphthalenyl]methylene]-2,5-cyclohexadien-1-ylidene]-N-methyl-, 1,1,2,2,3,3,4,4,5,5,6,6,6-tridecafluoro-1- hexanesulfonate (1:1) 1310480-28-4
Sulfonium, triphenyl-, 1,1,2,2,3,3,4,4,5,5,6,6,6-tridecafluoro-1-hexanesulfonate (1:1) 13044-10-09
Quinolinium, 1-(carboxymethyl)-4-[2-[4- [4-(2,2-diphenylethenyl)phenyl]- 1,2,3,3a,4,8b-hexahydrocyclopent[b]indol-7- yl]ethenyl]-, 1,1,2,2,3,3,4,4,5,5,6,6,6- tridecafluoro-1-hexanesulfonate (1:1) 1462414-59-0
Iodonium, diphenyl-, 1,1,2,2,3,3,4,4,5,5,6,6,6-tridecafluoro-1-hexanesulfonate (1:1) 153443-35-7
Iodonium, bis[4-(1,1-dimethylethyl)phenyl]-, 1,1,2,2,3,3,4,4,5,5,6,6,6-tridecafluoro-1-hexanesulfonate (1:1) 213740-81-9
Sulfonium, bis(4-methylphenyl)phenyl-, 1,1,2,2,3,3,4,4,5,5,6,6,6-tridecafluoro-1-hexanesulfonate (1:1) 341548-85-4
Perfluorohexane sulfon amides Several
Perfluorohexane sulfon amide 41997-13-1
Perfluorohexane sulfon halides Several
Perfluorohexanesulphonyl fluoride 423-50-7
Perfluorooctane sulfonic acid and its derivatives Several
Perfluorooctane sulphonic acid and its salts Several
Diethanolamine perfluorooctane sulfonate 70225-14-8
Ammonium perfluorooctane sulfonate 29081-56-9
Lithium perfluorooctane sulfonate 29457-72-5
Perfluorooctane sulfonic acid 1763-23-1
Perfluorooctane sulfonate 45298-90-6
Potassium heptadecafluoro-octane-1- sulphonate 2795-39-3
Ethanaminium, N,N,N-triethyl-, 1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,8- heptadecafluoro-1-octanesulfonate (1:1) 56773-42-3
1-Decanaminium, N-decyl-N,N-dimethyl- , 1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-heptadecafluoro-1-octanesulfonate (1:1) 251099-16-8
Perfluorooctane sulfon amides Several
Perfluorooctane sulfonamide 754-91-6
Heptadecafluoro-N-methyloctane sulfonamide 31506-32-8
Perfluorooctane sulfon amidoethanols Several
Heptadecafluoro-N-methyloctane sulfonamideoethanol 24448-09-07
1-Octanesulfonamide, N-ethyl-1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-heptadecafluoro- 4151-50-2
1-Octanesulfonamide, N-ethyl-1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-heptadecafluoro-N-(2-hydroxyethyl)- 1691-99-2
Perfluorooctane sulfon halides Several
1-Octanesulfonyl fluoride, 1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-heptadecafluoro- 307-35-7


Recomendations

  • Contact your raw material (yarns, fabrics, wet blue, trims) suppliers and explain that you require materials that conform to the AFIRM RSL on PFAS.
  • Consider performing risk-based testing of raw materials to ensure the current AFIRM RSL limits for PFAS are met.
  • Ensure that you purchase chemical formulations that meet the ZDHC MRSL V3.0 requirements for PFAS and are listed on the ZDHC Gateway at appropriate ZDHC MRSL Conformance Levels.
  • Request a GHS compliant Safety Data Sheet (SDS) from your chemical vendor.

References

  1. Agency for Toxic Substances and Disease Registry (ATSDR), Per- and Polyfluoroalkyl substances (PFAS) and your health, https://www.atsdr.cdc.gov/pfas/health-effects/overview. html (accessed November 2022)
  2. European Chemical Agency (ECHA), Perfluoroalkyl chemicals (PFAs), https://echa.europa.eu/ hot-topics/perfluoroalkyl-chemicals-pfas (accessed November 2022)
  3. Apparel and Footwear International RSL Management Group (AFIRM), Chemical information sheet, Perfluorinated and polyfluorinated chemicals, Version 2.0, March 2021, https://afirm-group.com/wp-content/uploads/2021/07/afirm_perfluorinated_polyfluorinated_chemicals_ v2.pdf (accessed November 2022)
  4. Research Institutes of Sweden (RISE), PFAS substitution guide for textile supply chains, Version 2, August 2022, https://www.ri.se/sites/default/files/2022-09/PFAS_Substitution_Guide_for_Textile_Supply_Chains.pdf (accessed November 2022)
  5. Interstate Technology Regulatory Council (ITRC), Per- and polyfluoroalkyl substances technical and regulatory guidance, June 2022, https://pfas-1.itrcweb.org/wp-content/uploads/2022/09/PFAS-Guidance-Document-9-2022.pdf (accessed November 2022)
  6. United States Environmental Protection Agency (EPA), Per- and Polyfluoroalkyl substances (PFAS), https://www.epa.gov/pfas/our-current-understanding-human-health-and-environmental-risks-pfas (accessed November 2022)
  7. European Environment Agency (EEA), Emerging chemical risks in Europe – PFAS, 12 Dec 2019, updated 02 March 2022, https://www.eea.europa.eu/publications/emerging-chemical-risks-in- europe (accessed November 2022)
  8. European Chemical Agency (ECHA), Registry of restriction intentions until outcome, Annex XV restriction proposals, Per- and polyfluoroalkyl substances (PFAS), 15 July 2021, updated 23 February 2022, https://echa.europa.eu/registry-of-restriction-intentions/-/dislist/ details/0b0236e18663449b (accessed November 2022)
  9. Danish Ministry of the Environment, The Danish Environmental Protection Agency, Alternatives to perfluoroalkyl and polyfluoroalkyl substances (PFAS) in textiles, 2015, https://www2.mst.dk/ Udgiv/publications/2015/05/978-87-93352-16-2.pdf (accessed November 2022)
  10. OECD/UNEP Global Perfluorinated Chemicals (PFC) Group, Portal on per and poly fluorinated chemicals, https://www.oecd.org/chemicalsafety/portal-perfluorinated-chemicals/alternatives/ (accessed November 2022)
  11. TÜV Rheinland LGA Products – Information, Analytical Service for per- and polyfluoroalkyl substances (PFAS), September 2022, https://www.tuv.com/content-media-files/master- content/rs/Attachments/3034_Information_2022_09_Analytical Service for per- and polyfluoroalkyl substances (PFAS)_en.pdf (accessed November 2022)
  12. California Legislative Information, AB-1817 Product safety: textile article: perfluoroalkyl and polyfluoroalkyl substances (PFAS), 29 September 2022, https://leginfo.legislature.ca.gov/faces/ billTextClient.xhtml?bill_id=202120220AB1817 (accessed November 2022)
  13. ZDHC manufacturing Restricted Substances List (ZDHC MRSL), Version 3.0) 01 November 2022, https://mrsl-30.roadmaptozero.com/ (accessed November 2022)
  14. bluesign - system black limits (BSBL), Threshold limit values for chemical substances in chemical products, Version 4.0, 01 July 2022, https://www.bluesign.com/downloads/bsbl/2022/bsbl_v40.pdf (accessed November 2022)