Decabromodiphenyl ether (commercial mixture, c-decaBDE)

A number of non-POP chemical alternatives are already on the market for the substitution of c-decaBDE in plastics and textiles. Furthermore, non-chemical alternatives and technical solutions such as non-flammable materials and physical barriers, respectively, are also available.

Note that the following information is extracted from the Risk management evaluation (UNEP/POPS/POPRC.11/10/Add.1)

C-decaBDE is a synthetic substance with no known natural occurrence that is used as a flame retardant (FR) in many applications worldwide, primarily in plastic polymers and textiles. Although fire regulations are mandatory for the market, there are no fire regulations that require the use of certain FRs in order to comply with these standards or regulations. Hence, it is up to the manufacturers to decide which technique to use. Alternatives to C-decaBDE can include FR substitution, resin/material substitution and product redesign as well as re-evaluation of fire-safety requirements.

The plastics industry is by far the major user of FR and the largest quantities of FR are supplied to raw-material manufacturers. The amount of c-decaBDE used in plastics and textiles globally varies but up to 90% of c-decaBDE ends up in plastic and electronics while the remaining ends up in coated textiles, upholstered furniture and mattresses. Electrical and electronic equipment (EEE) applications include casings for EEE, wire and cable, and small electrical components. Other identified uses of c-decaBDE flame-retarded plastics are in buildings, construction materials, in storage and distribution products such as plastic pallets, in the transportation sector (cars, airplanes, trains and ships).

The aviation industry still uses c-decaBDE in electrical wiring and cables, interior components, and EEE in older airplanes and spacecraft. C-decaBDE is expected to be present in plastics and textiles in several waste streams such as “End of Life Vehicles” (ELV), e-waste, textile- and mixed waste.

Technically feasible alternatives appear to be available for all applications, however, service and replacement of legacy spare parts in articles already in use is not always practicable due to the need for testing of reconfigured parts often in original vehicles, which are no longer in mass production and often have not been for many years. This also applies for aircrafts currently in production under existing certificates.

Alternatives available for use in plastics

For plastics in EEE, substitution strategies range from exchange of the resin system and FR, to complete redesigns of the product itself. According to the EU restriction proposal, which assessed different alternatives to c-decaBDE, Eight possible alternative chemicals appear to be possible substitutes for c-decaBDE in plastic polymers:

(a) Decabromodiphenyl ethane (DBDPE);

(b) Bisphenol A bis(diphenyl phosphate) (BDP/BAPP);

(c) Resorcinol bis(diphenylphosphate) (RDP);

(d) Ethylene bis(tetrabromophthalimide) (EBTBP);

(e) Magnesium hydroxide (MDH);

(f) Triphenyl phosphate (TPP);

(g) Aluminium trihydroxide (ATH);

(h) Red phosphorous.

 Alternatives available for use in textiles

C-decaBDE has traditionally been applied to textiles used in transportation (public transit buses, trains,aviation and ships),  draperies for use in public occupational spaces, furniture of high-risk occupational areas such as nursing homes, hospitals, prison and hotels, and military for tarps, tents and protective clothing, but are not used in consumer clothing.  C-decaBDE is used as a back-coating in combination with antimony oxide (ATO) as a synergist. According to U.S. furniture industry sources in 99% of cases, chemical FRs will not be needed to meet pending national standards for residential upholstery. However, FRs are still widely used in furniture.   

There is no single replacement for c-decaBDE for textiles applications but viable approaches exist. A number of affordable options are available to replace c-decaBDE uses in furniture, mattresses, draperies and other textile applications. Substitution options for textiles range from brominated additive FRs such as DBDPE, to alternative techniques and inherent flame-resistant materials; DBDPE [T4] would be the preferred alternative to c-decaBDE in textiles.

The most common FR for polyester is polyethylene terephthalate with built-in phosphorus on the polyester backbone and is considered a good substitute for the c-decaBDE/antimony flame retardant in clothing and draperies.

The following seven substances were identified as the most likely chemical alternatives to the use of c-decaBDE in textiles :

(a) Aluminum trihydroxide (ATH);

(b) Magnesium hydroxide (MDH);

(c) Tris(1,3-dichloro-2-propyl) phosphate (TDCPP);

(d) Ethylene bis(tetrabromophthalimide) (EBTBP);

(e) 2,2'-oxybis[5,5-dimethyl-1,3,2-dioxaphosphorinane] 2,2'-disulphide;

(f) Tetrabromobisphenol A bis (2,3-dibromopropyl ether) (TBBPA) (only in polymer applications);

(g) Red phosphorous;

(h) Decabromodiphenyl ethane (DBDPE).

There are several chemical non-halogen c-decaBDE substitutes available for natural cellulose or protein fibres such as cotton, wool, rayon (viscose, modal and lyocell), and linen. They include:

(a) Ammonium polyphosphates;

(b) Dimethylphosphono (N-methylol) propionamide;

(c) Phosphonic acids such as (3-{[hydroxymethyl]amino}-3-oxopropyl)-dimethyl ester;

(d) Tetrakis (hydroxymethyl) phosphonium urea ammonium salt.

C-decaBDE is used in sealants, adhesives, architectural foam, and coatings as well as in some applications in buildings and construction. C-decaBDE is used in wall and roof panels, which are typically made from unsaturated polyester (UPE) glass composites; floor tiles; and commercial grade carpeting. C-decaBDE is also used in insulation materials, roofing materials such as membranes and films for use under roofs to protect building areas. C-decaBDE can also be found in ducting elements such as the duct covering or insulation. The following six chemicals have been identified as alternative substances for these applications:

(a) Magnesium hydroxide (MDH);

(b) Aluminum trihydroxide (ATH);

(c) Ethylene bis(tetrabromophtalimide) (EBTBP);

(d) Substituted amine phosphate mixture (P/N intumescent systems);

(e) Red phosphorous

(f) Decabromodiphenyl ethane (DBDPE).

Alternative techniques to improve fire safety exist such as inherent flame-resistant material, use of different technical solutions, i.e. barriers or complete redesign of the product.

Metal or inherently flame-resistant plastic can be used as alternative materials; intumescent systems, nanocomposites, expandable graphite, smoke suppressants, polymer blends, and layering are other options. Halogenated polymers such as PVC have FR properties because they release halogen radicals during combustion; however, like brominated FRs, PVC may form dioxins and acids upon combustion and are therefore not a preferred alternative FR material.

The following are polymer materials that are inherently flame-retardant and which might be considered as a substitute to c-decaBDE-based polymers such as poly(butylene terephthalate) (PBTE) or polyamide/ nylon (PA):

(a) Halogen-free polyketone (this is considerably more costly than PBTE and PA);

(b) High performance thermoplastics such as polysulphone, polyaryletherketone (PAEK) or polyethersulphone (PES).

Polymers that char such as polyimides, polyaramides, liquid crystal polyesters, polyphenylene sulphide, polyarylenes and many thermosets also tend to have a greater resistance to fire. Where the base polymer has FR properties, depending on the end use, a sufficient level of fire performance may be achieved without the need for chemical FRs or much lower loadings may be required.

It may be necessary to change product designs to adopt these alternative materials and their implementation would require higher level of research and development activities than the substitution of c-decaBDE with a FR drop-in chemical replacement.

Redesign has successfully replaced c-decaBDE in several EEE applications: for example, separating high-voltage components that need greater ignition protection from low-voltage components; reducing operating voltage requirements and therefore reducing the need for flame-retarded enclosure materials; removing sources of ignition; reducing operative voltage; removing the power supply from the product.

Products can be redesigned to incorporate non-flammable materials or barrier technologies. Two approaches are suitable: 1) use of cover fabrics made from materials that are inherently fire resistant, 2) use of fire-resistant barriers between the cover fabric and the flammable cushioning foam.

A number of synthetic fibres are inherently flame resistant, including aramid, viscose, novoloid, polyamides, and melamine. Inherently flame resistant fibres like polyhaloalkenes> contain halogens such as polyvinyl chloride and vinyl bromide, while others are halogen free, including polyaramides and melamine fibres>.  Other inherently flame-retarded materials include rayon with a phosphorus additive, polyester fibres, and aramids. In addition> some natural materials like leather and wool have inherently fire-resistant properties. Blending natural and synthetic fibres is another approach: ‘poly-cotton’; cotton-nylon; or cotton or polyester blended with melamine.

In furniture, barriers can be used between the surface fabric and the interior foam core. These can be made from inherently flame-retarded fibres such as wool, para aramids, melamines, modacrylics, or glass fibre. In addition, many of these fibres are made from non-halogen materials. Plastic films have also been used as barriers, especially films made of inherently flame-resistant plastics such as neoprene (polychloroprene). Cotton-batting materials treated with boric acid have also been used; however there are some toxicological concerns with boric acid.

Intumescent systems: Intumescence is the formation of a foamed char, which acts as heat insulation. Intumescent systems include use of expandable graphite impregnated foams, surface treatments and barrier technologies of polymer materials. Intumescent systems may not be applicable to the same sets of textiles as brominated FR-based back-coatings.

Flammability standards: Fire toxicity is the largest cause of death and injury in fires but is usually not taken into account. An overall reduction of flame-retarded materials may therefore lead to a smaller risk of health problems for the general public and fire fighters, if fire safety can be achieved by other means. For example, Californian furniture flammability standards have been changed such that future use of FRs can be excluded.

Reduced ignition propensity (RIP): As cigarettes are a common cause of fires. Requiring that all cigarettes sold have reduced ignition propensity is an effective method to reduce fire risk.

For further information, please refer to

• UNEP/POPS/POPRC.5/10/Add.1 – General guidance on considerations related to alternatives and substitutes for listed persistent organic pollutants and candidate chemicals
• Risk profile Ar, Ch, En, Fr, Ru, Sp (PDF)
• Risk management evaluation Ar, Ch, En, Fr, Ru, Sp (PDF)