ZDHC Guidance Sheet



Flame retardants are chemicals that are usually added intentionally to textile or footwear articles to meet legal and contractual flammability standards.1 By adding these chemicals the finished article’s ability to ignite is reduced. Flame Retardants are typically not used in day to today fashion clothing.

The common uses for flame retardants are; electric and electronic equipment (i.e. TV sets and personal computers), the construction industry, the transport industry.2 Textile applications focus on furniture upholstery, carpets and curtains for public buildings like theatres and cinemas, automotive/aircraft/trains interior textiles, certain personal protection workwear e.g. for fire fighters.

Uses in textile & footwear supply chains

Historically, flame retardants have been applied to textiles during processing. Leather and footwear articles are rarely equipped with flame retardants. Flame retardants can be applied as a back coating or by the padding method.

Flame retardants can be applied directly, as blends or as a topical finish. These days flame retardants are typically used in very specialised technical applications such as firefighting or military gear and protective clothing.

Harmful effects of Flame retardants

There are a lot of various species of inorganic and organic chemicals based on halogen, phosphorous and nitrogen compounds that can provide flame retardant properties to articles. In view of the big variety of these chemicals it is not possible to assign general toxicological properties to the whole range of flame retardants.

However, certain brominated flame retardants have been linked to endocrine disruption and thyroid dysfunction.3 Some of the organophosphate chemicals used as flame retardants could pose a risk to bone and brain health.4

Polybrominated diphenyl ethers (aka PBDEs) are scrutinised for its delayed mental and physical development and reduced fertility.5

Tetrabromobisphenol A (TBBPA), which is used in plastic paints, synthetic textiles and electronic devices is known to cause cancer and therefore proposed for harmonised classification in EU CLP as well as included in the EU SVHC Candidate List since January 17th, 2023.6

Apart from this, many of the organic flame retardants are considered persistent and are known to bioaccumulate inside living organisms.7

Chemistry and Terminology

The ZDHC MRSL V3.1 lists a total of 32 chemicals under the flame retardant category. Apart from this SCCPs and MCCPs, chemicals put under the heading of chlorinated paraffins are also known to be sometimes used as flame retardants. All these chemicals can be classified into three groups.

  1. Inorganic flame retardants
  2. Organophosphorus and/or organonitrogen flame retardants
  3. Halogenated organic flame retardants (organochlorines or organobromines)

Flame retardants interfere with the combustion process (e.g. during heating, decomposition, ignition of flame spread). The way they achieve this could be by;8

  • Triggering an endothermic process by the flame retardant.
  • Forming a protective layer so that the heat transfer or pyrolytic gases are cut-off from oxygen.
  • By diluting the gases evolved during ignition, which are responsible for sustenance of the flame.

1.1 Inorganic Flame Retardants:

Inorganic flame retardants are essentially the inorganic salts used for their properties of being flame retardants. Some of the inorganic flame retardants that are banned from intentional use in textile and footwear manufacturing as per the ZDHC MRSL V3.1 are listed below:

Chemical CAS No.
Boric acid 10043-35-3 / 11113-50-1
Diboron trioxide 1303-86-2
Disodium octaborate 12008-41-2
Disodium tetraborate anhydrous 1303-96-4 / 1330-43-4
Tetraboron disodium heptoxide hydrate 12267-73-1

1.2 Organophosphorus Flame Retardants:

Organophosphorus flame retardants are the most widely used category of flame retardants in textiles. These could be phosphates or phosphine oxides. The list of organophosphorus flame retardants banned from intentional use as per the ZDHC MRSL V3.1 are listed below:

Chemical CAS No. Notes
Trixylyl phosphate 25155-23-1
Tris (2,3 dibormopropyl) phosphate 126-72-7 Also classified as halogenated
Tri (2-chloroethyl) phosphate 115-96-8 Also classified as halogenated
Tris (2-chloro-1-methylethyl) phosphate 13674-84-5 Also classified as halogenated
Tris (1,3-dichloroisopropyl) phosphate 13674-87-8 Also classified as halogenated
Tris (1-aziridinyl) phosphine oxide 545-55-1
Trimethyl phosphate 512-56-1
Tri-o-cresyl phosphate 78-30-8
Bis(2,3-dibromopropyl)phosphate 5412-25-9

1.3 Halogenated organic flame retardants:

Halogenated organic flame retardants are the biggest class of the flame retardants used in textiles. These flame retardants can be further classified as either chlorinated flame retardants or brominated flame retardants. Many halogenated organic flame retardants are notoriously known for their persistence in the environment and bioaccumulation in living organisms. Therefore, there are for many years concerns about the risk/benefit ratio for these chemicals pose to public health for its application. The following list of chemicals from the ZDHC MRSL V3.1 are banned from intentional use in textile, leather and footwear industries.

Chemical CAS No.
2,2-Bis(bromomethyl)-1,3-propanediol 3296-90-0
Decabromobiphenyl 13654-09-6
Decabromodiphenyl ether 1163-19-5
Dibromobiphenyls Multiple cas nos
Heptabromodiphenyl ether 68928-80-3
Hexabromocyclodecane 3194-55-6
Hexabromodiphenyl ether 36483-60-0
Monobromobiphenyls Multiple cas nos
Nonabromodiphenyl ether 63936-56-1
Octabromobiphenyls Multiple cas nos
Octabromodiphenyl ether 32536-52-0
Pentabromodiphenyl ethe 32534-81-9
Tetrabromobisphenol A 79-94-7
Tetrabromobisphenol A bis (2,3-dibromopropyl ether) 21850-44-2
Tetrabromodiphenyl ether 400088-47-9
Tribromodiphenyl ethers Multiple cas nos

Safer alternatives to flame retardants

The flame retardants used in the textile and leather industries are highly selective and application specific. Therefore, it is still a challenge to find an exact match to replace them with less hazardous chemicals. However, if alternatives are found to be effective in textile or leather applications, it is recommended that a case-to-case study and a phase-out process is carried out to replace the current usage of these ZDHC MRSL restricted substances.

Any alternative selected must be carefully vetted to ensure a regrettable substitution is not made. Including checking it is conformant to the latest version of the ZDHC MRSL. In the past many regrettable substitutions were tried and therefore any new substitution needs to be tested on several levels before it can be deemed safer.

In certain cases where flame retardants are used in polymers, it is recommended to be incorporated during the polymerisation steps, reducing the chances of it leaching into the environment. However, the overall hazard and possible leaching still needs to be tested. Following table lists some of such chemicals that have been proven to be effective as flame retardants.

  1. Metal hydroxides/oxides These may not be used on textiles directly as a flame retardant but can be used as fillers with conjunction of flame retardant.
    • Aluminium oxide (ATH-Aluminium trihydrate)
    • Aluminium oxide
    • Magnesium hydroxides
  2. Dimethyl phosphono(N-methylol)propionamide
  3. Diguanidine hydrogen phosphate Mainly used in polycarbonate plastics
  4. Poly(phosphonate-co-carbonate)9
  5. Ammonium polyphosphate (APP) Used in paints and coatings as a safer alternative to brominated flame retardants.10 It can also be used as a filler along with other flame retardants in upholstered furnitures, mattresses, foams and carpet backing.

Important Regulations

Because of their hazardous properties, flame retardants are highly regulated chemicals covered by global legislation:11

  • EPA regulates new and existing chemicals, including flame retardants, under the Toxic Substances Control Act (TSCA).12
  • Other agencies, such as the Consumer Product Safety Commission (CPSC), have the authority to regulate the safety of consumer products that may incorporate flame retardants to meet fire safety standards.13
  • Since 1st March 2021 the European Union has banned the use of halogenated flame retardants in electronic display enclosures and stands.
  • The Furniture and Furnishings (Fire) (Safety) Regulations 1988 (UK).14
  • Fire behaviour of building materials and building components (DIN 4102; Germany).15

Relevance to the ZDHC MRSL

In general all flame retardants used in textile, leather, footwear, or other chemicals need to conform to the latest version of the ZDHC MRSL.

The use of the flame retardants listed in the ZDHC MRSL V3.1, or any halogenated flame retardant, is not permitted (for fashion, sport or outdoor clothing and apparel and home textiles).

It should be noted that there are certain critical (e.g. technical textile) end uses where legally or contractually mandated standards may only be achieved using these substances (e.g. military, medical, protective clothing, public transportation and public buildings). The formulations will always be deemed ZDHC MRSL NON-CONFORMANT and it is intended that the ZDHC Supplier Platform will appraise the end uses of any flame retardants within an inventory.


  • Ensure you purchase chemical formulations that meet the ZDHC MRSL V3.1 requirements for flame retardants and that are listed on the ZDHC Gateway at appropriate ZDHC MRSL Conformance Levels.
  • Request a GHS compliant Safety Data Sheet (SDS) from your chemical vendor.


  1. ECHA- Strategy for flame retardants (March 2023 edition) https://echa.europa.eu/documents/10162/2082415/flame_retardants_strategy_en.pdf/ (assessed in July 2023)
  2. Phosphorus, Inorganic and Nitrogen Flame Retardants Association https://www.pinfa.eu/
  3. Leonetti et al. Environmental Health (2016) 15:113, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5123327/pdf/12940_2016_Article_199.pdf
  4. Patisaul et al. Toxicological Sciences, (2020) 176(1): 203, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7357193/pdf/kfaa046.pdf
  5. Eskenazi et al. Environmental Health Perspectives, (2013) 121(2): 257 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3569691/pdf/ehp.1205597.pdf
  6. NTP Technical Report on the Toxicology Studies of Tetrabromobisphenol A https://ntp.niehs.nih.gov/sites/default/files/ntp/htdocs/lt_rpts/tr587_508.pdf
  7. PCBs, PBBs and Brominated Flame Retardants, EPA. https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=283728&Lab=NHEERL
  8. Clariant Corp. Flame retardants online, https://www.flameretardants-online.com/flame-retardants/inorganic
  9. Market Place by ChemSec https://marketplace.chemsec.org/Alternative/Nofia-Colpolymers-Halogen-Free-Flame-Retardants-for-Resin-Systems-1246
  10. Market Place by ChemSec https://marketplace.chemsec.org/Alternative/Ammonium-Polyphosphate-flame-retardant-847
  11. European Chemical Agency (ECHA WEBSITE) https://echa.europa.eu/-/echa-identifies-certain-brominated-flame-retardants-as-candidates-for-restriction
  12. American Chemistry Council's North American Flame Retardant Alliance https://www.flameretardantfacts.com/about-flame-retardants/regulations/
  13. Consumer Product Safety Commission article on Flame Retardant, https://www.cpsc.gov/Business--Manufacturing/Business-Education/Business-Guidance/flame-retardants
  14. The Furniture and Furnishings (Fire) (Safety) Regulations 1988 https://www.legislation.gov.uk
  15. Furniture and Furnishings (Fire Safety) Regulations 1988/1989, 1993 and 2010 : Firesafe.org.uk Products https://www.din.de


EPA Environmental Protection Agency
GHS Globally Harmonised System
MCCP Medium-chain chlorinated paraffins
MRSL Manufacturing Restricted Substances List
SCCP Short-chain chlorinated paraffins