This group of chemicals is diverse and may lead to a long list of different effects on health and environment. The most severe of these are the possibility of causing cancer and genetic defects, and that they may affect fertility or the unborn child.
Most of the compounds are regarded as toxic or harmful to aquatic life, with long-lasting effects, and several of them also fulfil the criteria to be regarded as persistent, bioaccumulative and toxic (PBT).
Compounds in this group may also harm public health and the environment by destroying ozone in the upper atmosphere.
Function and use
Polyhalogenated compounds can have a range of properties including flame-retarding, plasticising, biocidal, fat-dissolving, water-repellent, cooling and/or lubricating.
In contrast to flammable materials that mainly contain hydrogen and carbon, brominated flame retardants are much more difficult to ignite and can be incorporated in materials in various ways to give fire protection.
Chloroparaffins (such as SCCP) can act as plasticisers, lubricants and/or as flame retardants. Chlorophenols (such as PCP) have mainly been used as a multifunctional biocide.
Areas of application
Flame retardants are used to delay the time it takes for a material to catch fire or to prevent it altogether. Textiles and furniture in public places, protective clothing, rubber cables, insulation material and electric and electronic equipment are examples of products that can contain flame retardants.
Chloroparaffins are used, for instance, in coolants and lubricants in the metalworking industry and as additives in jointing compounds like paints, plastics and rubber. They may also be used in agricultural seeds (for non-food uses), leather, masonry, wood preservation, cooling-tower water, rope and paper. Their use has declined due to their high toxicity and slow biodegradation.
Chlorophenols can be found in materials such as plastics, textiles, wood and building products, in which biocides often are used. Chlorinated aromatic hydrocarbons are frequently used in the manufacturing of dyes.
Several brominated flame retardants are restricted in POPs, the RoHS Directive, REACH annex XVII or included in the REACH Candidate List. Some chlorinated aromatics are restricted in POPs, REACH annex XVII or for use as pesticides.
Short-chain chloroparaffins (SCCPs) are restricted in POPs and included in the REACH Candidate List, and several halogenated solvents are restricted in REACH annex XVII. The chlorophenol PCP is restricted in REACH annex XVII.
The most efficient way to phase out the use of halogenated compounds is to substitute them for alternative materials that do not require the addition of this type of substances. Textiles made purely from natural fibres like wool, silk, cotton and hemp are less flammable than mixtures with synthetic fibres like polyester and nylon.
An alternative approach to using halogenated biocides is to use materials and products that will not require biocides (e.g. are easy to clean).
IT equipment contain several substances that are categorized as hazardous. These include flame retardants, used to prevent products from catching fire. Safer alternatives on TCO's Certified Accepted Substance List are:
890525-36-7, 2791-22-2, 2791-23-3
Bisphenol A diphosphate
Siloxanes and silicones, di-Me, di-Ph, polymers with Ph silsesquioxanes
Substituted Amine Phosphate mixture
Tetrakis (2,6-dimethylphenyl)-m-phenylene biphosphate