The group of flame retardants that are most critical includes the following organohalogen compounds that are still admissible in the EU: halogenated biphenyls, terphenyls, naphthalenes and diphenyl methanes, brominated diphenyl ethers, tetrabromobisphenol A, short-chain chloroparaffins C10–13, and halogenated phosphoric acid esters.
- Halogenated biphenyls, terphenyls, naphthalenes and diphenyl methanes are especially hazardous to the environment and have thus already been prohibited in Austria and Switzerland.
- Many brominated flame retardants are very difficult to biodegrade and accumulate in living beings. In the case of fire and uncontrolled disposal, they form corrosive flue gases, which may contain highly toxic brominated dioxins and furans.
- The three brominated flame retardants that are most frequently used are tetrabromobisphenol A (TBBPA), decabromodiphenyl ether (DecaBDE) and hexabromocyclododecane (HBCD). These three substances have been detected in distant polar regions as well as in breast milk. In addition, they are toxic to aquatic organisms to different degrees, and may have adverse long-term effects on humans and the environment. The German UBA environmental agency recommends that these substances should no longer be used. (Leisewitz 2000)
- Brominated diphenyl ethers are regarded as highly hazardous to health (carcinogenic) and to the environment. In the German-speaking countries, they meanwhile account only for a small share of the flame-retardant market. However, in the rest of Europe, and particularly in the Asian and American markets, this trend is far less pronounced. A study published by the German UBA environmental agency states that the most important brominated diphenyl ether (i.e. decabromodiphenyl ether) should be substituted, due to its persistence in sediments, indoor air and outdoor air. [Zwiener 2006]
- Tetrabromobisphenol A has not been classified as toxic to humans but as toxic to aquatic organisms. Furthermore, it is very persistent in the environment, and small concentrations of this substance have been detected in organisms at the end of the food chain. For instance, in Europe it was found in falcon tissue and raptor eggs in Greenland, as well as in human breast milk. In the case of fire or uncontrolled disposal, the bromine contained in TBBPA may also contribute to the formation of dioxins and furans. (Leisewitz 2000)
- The EU has classified short-chain chloroparaffins as dangerous to the environment and possibly causing cancer (C3). [Zwiener 2006]
- Halogenated phosphoric acid esters may be reprotoxic, carcinogenic and neurotoxic. Today, the most important substance in this group is TCPP (tris (chloropropyl) phosphate). There are indications of mutagenic properties of TCPP, and it is suspected of having carcinogenic effects. [Zwiener 2006]
- In the case of fire, highly toxic substances are formed, e.g. dioxins and furans.