Wool is a keratin-based fibre and is therefore a food source for various insects (larvae), the best known of which are moth larvae. A wide variety of chemicals can therefore be used to protect wool fibres. However within the GUT system, the only active ingredient which is approved for the protective finishing of wool fibres is permethrin.
There are 3 classifications of protection for wool which differ according to the amount of permethrin applied and therefore the level of protection gained. The maximum amount allowed is 210 mg permethrin per 1 kg wool. Wool carpets must therefore always be labelled as follows:
Protection class 1: The wool fibres contain no permethrin and are not treated
Protection class 2: The wool fibres are treated with permethrin for normal protection against moth and beetle infestation. The maximum concentration is 150 mg/kg
Protection class 3: The wool fibres are treated with permethrin for high protection against moth and beetle infestation. The maximum concentration is 210 mg/kg.
Only those processes may be used which ensure that the fibre is finished in a durable way. Spray applications are not permitted.