RSL - List of restricted substances in shoes

"Sustainability and environmental protection are the key issues that the cads organization – cooperation for assuring defined standards for shoe and leather goods production (a registered association) - deals with. Its priority is the prevention of dangerous substances in shoes. To achieve this objective, cads members, among them the chemical industry, manufacturers of materials and manufacturers of the shoe, leather goods and textile sector as well as important commercial enterprises, attach great importance to applying the strict values that often exceed the official guidelines not only within their own production processes but also to disseminate them worldwide along the entire supply chain among the manufacturers of materials and the supplier industry.

Since various limits apply in the individual countries, our objective is to set minimum requirements. This also serves the purpose of promoting the dialogue about critical substances with non-governmental organizations. Our efforts culminated in the first version of a joint guideline published in 2013, which had a considerable worldwide response.

The present “List of Restricted Substances in Shoes” was published in close coordination with independent testing and research facilities. All companies that voluntarily belong to cads commit themselves to achieve the consciously set ambitious objectives. In most cases, the voluntary commitment of the cads members even clearly exceeds statutory requirements.

I am sure that the importance of the issues of sustainability and environmental protection will become even more important in the future. For this reason, we recommend all companies of the shoe and leather goods sector to choose a precautionary approach when dealing with the environment and to take initiatives that create a higher sense of environmental responsibility. Join us in our path that leads to pollutant-free, sustainable and environmentally compatible production. Support us in becoming a little better every day! "

Michael Tackenberg
Chairman of the board

AZO Dyes

Azo dyes are dyes which contain at least one azo bond (-N = N-) within the molecule. Azo dyes are lightfast and acid-stable. In textiles and leather, azo dyes are commonly used as colorant.
Certain azo dyes, when in a basic chemical environment or under certain enzyme conditions, can release dangerous aromatic amines.

The statutory requirement for these aromatic amines from azo dyes is 30 mg/kg in the EU.

cads has specified that value to be reduced by one third to
20 mg/kg which also takes account of the legal requirements in China.


Biocides are biologically active substances, and their toxic and biocidal nature enables them to kill or harm living things. Therefore they are used for mould prevention or as a disinfectant. Biocides have adverse effects on the nervous system when entering into the human body. They may irritate eyes, skin, and the respiratory system. In the manufacture of leather bicides have to be used as product preservation to protect the wet intermediates. In order to prevent excessive use cads uses limits for the biocides based on the requirements of the Blue Angel for shoes.

cads has reviewed the listed substances and pronounced the compliance with the maximum regulatory limits and has fixed sometimes lower limits.

Chlorinated Phenols

In tanneries and the pulp industry the listed chlorinated phenols are used as fungicides, insecticides and bactericides. They are toxic and can be dangerous. For chlorinated phenols exist partially regulations which specify quantity limits, a few of them are prohibited in some states.

cads sets lower limits as given in the legal guideline, in some cases significantly or has set for undeclared substances maximum amounts.

Dyestuffs (allergenous, carcinogenic, others)

Disperse dyes are generally water-insoluble colorants that are mainly used for coloring polyester, nylon and cellulose acetate textile fibers. They have extremely high fastness to light for very pale colors. Some disperse dyes have an allergenous (sensitizing) potential to human skin and some are partly classified as carcinogenic.

cads respects the different requirements and has scheduled for the use of the listed substances a general limit of 3,3 mg/l (50 mg/kg).

Heavy metals

Heavy metals are available in colorants and used as dye-fixing agents. They are also used as stabilizers in plastics. Many heavy metals are bioaccumulative when absorbed by human body through perspiration and give cause for concern in health terms. The listed heavy metals are supposed to technical regulations.

cads has defined additional limits which are based on the
prior art.

Organotin comounds

The major commercial applications of organotin compounds are as plastic stabilizers, catalysts, industrial biocides, antifouling paints, glass coatings, and pesticides. They are also used as disinfectant for textiles, leather and pulp. Organotin compounds are environmental pollutants and particularly dangerous to aquatic creatures.

cads has appointed limits that are a fraction of the allowed values.

Other chemical residues

Many materials can be equipped with special chemicals to produce water- and soil-resistant properties or to prevent shrinkage. Furthermore, chemical substances remain as residues of the manufacturing process in the material, whereby possible health risks by migration in contact with the skin can not be excluded.

cads has fixed stringent limits in consideration of the production-related feasibility.

Perfluorinated substances

Perfluorinated and polyfluorinated substances are non-naturally occurring substances in which hydrogen atoms have been replaced by fluorine. The best known representatives of this class of substances are PFOS (perfluorooctanesulfonic acid) and PFOA (perfluorooctanoic acid). These substances are used as water and oil repellent impregnating agents. They are persistent in nature as well as bioaccumulating and are not or are degraded to a very small extent.

Based on legal requirements and technical feasibility, cads has set its strict limits here.

Other phenols

Alkylphenols are used as plasticizers in plastics and for the production of alkylphenol ethoxylates, which are used as nonionic surfactants. APEOs are biodegradable persistant and may have hormonal effects.

Based on legal requirements and campaigns by NGOs, cads has reduced the requirements clearly.


Phthalates have diverse uses in modern commerce. One of their primary uses is as a plasticizer in flexible plastic products. They are also used as fixatives, detergents, lubricating oils, and solvents.

As a result of these diverse uses, phthalates are found in many consumer products, such as textiles, footwear, cosmetics.
Phthalates can result in health problems.

cads, in his position as a pioneer, shows that the reduction of Phthalates is possible and reduces the existing legal requirements for shoes and leather goods.

Polycyclic Aromatic Hydrocarbons

PAHs are produced by the incomplete combustion of organic materials such as wood, oil and animal fats. PAHs are less water-soluble, evaporable and degradable and attach themselves to organic particulate matter. PAH contaminations have been found not only in rubber but also in various plastics, because they will be inserted by the used plastcizer oils or carbon black as coloring agent.

Since the end of 2015 some PAHs are regulated by law. Previously and currently cads decreases current legal limits significantly.

Volatile Organic Compounds (VOC)

Although the industry is endeavouring to dispense with substances containing solvents, solvents are neccessary for the manufacture of shoes in the form of adhesive and finish, which evaporate slowly during the transportation and by usage.

Inter alia substances such as acetophenone and 2-phenyl-2-propanol can be formed in the case of incorrect process control for the production of ethylene vinyl acetate materials (EVA). Both substances are classified as harmfull and have a strong Odour. In addition 2-Phenyl-2-propanol is supposed to have an allergenic potential.

cads limits for VOCs are based on the concentrations reachable with the best available technologies.

Chlorinated benzenes and toluenes

Chlorinated benzenes and toluenes are chlorinated aromatic compounds. In addition to the adverse health effects of these compounds they are also questionable from an environmental toxicological point of view. Mainly the chlorinated benzenes and toluenes are used as tools / solvents in the dyeing of synthetic fibers. Some of these compounds are used as biocides. According to today‘s state of the art these tools can be replaced by safer alternatives.

cads regulates the use of these compounds from its own commitment to protect workers, consumers and the environment.

Flame Retardants

Flame Retardants are used to make easily flammable materials like plastics or synthetic textiles, for example, more resistant for applications under higher temperatures, flying sparks or open flame. Flame retardants represent a large group of chemicals; there are halogenated organic flame retardants, non-halogenated organic flame retardants and inorganic flame retardants. Their function is also extremely varied – thus, flame retardants are often used as plasticizers as well. Some flame retardants persist for a long time, i.e. they can accumulate permanently in the environment, which is why their use has been restricted.