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Leather facts

Essay seven: Standards and use limitations for chemicals in leather production

Nothing to fear: Good practice and regulation keep industry safe

Dr Alois Püntener, VESLIC, Association of Swiss Leather Chemists and Technologists

Chemicals are used in every step of leather production but they are stringently regulated and tanneries provide safe, clean environments to work in. Responsible tanneries all over the world recycle skins to create a valuable product and are part of the solution, not the problem.

The use of leather and fur dates back almost as long as recorded history, protecting our ancestors when they went out to hunt. They used a lengthy and fairly sophisticated process to tan hides and skins to make them durable: if they’d simply dried the skin the leather would be too tough, if they kept it moist, skins would have rotted and decayed. The preparation of animal skins was one of our ancestors’ first crafts, probably first carried out by women, and later, in the pre-industrial times, mostly by men. The animal skin was not only used as jewellery and camouflage or for protection but also for tools, household items and shoes – the shoemaker was one of the most important downstream users in early times.
These original tanners developed innovative techniques and used chemicals to make the skin strong, durable and fashionable1. The know-how was passed on from father to son, and subsequent trade guilds protected the secrets of the process. It has never been reported that leather or leather-making was harmful or caused sickness.
However, dealing with the rotting skin and chemicals released an unpleasant odour and tanners tended to be housed in particular areas, often near flowing water, downstream from the city. In 1700, Italian physician Bernardino Ramazzini, who specialised in occupational diseases, reported that an accumulation of tannery waste, and particularly the smell, could be damaging to health2. At the time, the standard of cleanliness in European tanneries – as in many industrial workplaces – was not high, but the tannery itself was not thought to be a bad environment. In fact, the tangy resin aroma of vegetable tanning agents had been recommended as a treatment for lung disorders and tanning liquor was used to treat some skin diseases.
In Johann Christian Gottlieb Ackermann’s translation of Ramazzini’s work it mentions that in the Polish city of Gdansk, which had been ravaged by the plague, only the tanners’ street was not affected3. We can probably assume the disinfecting effect of the tanning liquors killed the bacteria Yersinia pestis, transmitted by the bites of fleas.

Modern-day processes

The leather industry has progressed immensely from those early times. Leather production has continuously improved with respect to the quality of leather, environ­mental protection, waste minim­isation and disposal, the correct use of chemicals and industrial accidents4. Leather production still generates by-products, which find outlets in several sectors such as fine chemicals, photography, cosmetics and as soil conditioners and fertilisers. Tanneries have been successful in protecting the environment, and workers are treated with respect in safe work places5.
However, due to cost pressures, some tanneries have moved to developing countries, where about twice as much leather is now produced than in developed countries6. It is simply unacceptable that while most tanners spend huge amounts of money and time building treatment plants and protecting the environment and workers, a small minority do not, thinking that in developing countries, similar laws are not in place.
Irresponsible and careless media articles make the public think the worst cases are the standard; suggesting neither the owners nor the governments are looking after workers, the environment or consumers’ health and safety. This is simply not the case.

Vital chemicals

In the hands of a skilled tannery, with recipes for good tanning liquor and smoothing finishing oils, outstanding quality leather can be produced. Chemicals are used throughout the process, from the soaking to remove soil and other contaminants and to increase moisture, all the way to the finishing stage, when the leather is treated to give its final appearance and qualities.
The Globally Harmonized System of classification and labelling of chemicals (GHS) is an internationally agreed system created by the United Nations7. It is designed to use consistent criteria for description, classification and labelling on a global level for all available chemicals. The information  is intended to help the tannery to take the necessary measures and to show that the manufacturing process does not present an unjustifiable risk, and that undesirable chemicals will not be found in the end products. One has to wonder why some leather buyers neglect tanneries which invest a lot of money cleaning their waste, have good working conditions and make high-quality leather. They should clearly prefer such responsible enterprises even if the leather is not as cheap.

Global industry

The global nature of the industry presents its own issues. Leather goods are transported over long distances, but in warm and wet climates this requires the use of biocide products to avoid damage to the leather caused by mould, which can also occur in vegetable-tanned leather.
Biocidal products contain or generate active substances that defend against harmful organisms such as pests and bacteria. A few years ago, inappropriate biocides were found on leathergoods due to incorrectly impregnated packaging and packaging aids, and they caused some skin reactions. This led to a mistaken theory that tanning agents trigger allergies – and this suspicion remains today, unfortunately. Therefore, it is not only tanneries but also article manufacturers and retailers that should use such products cautiously and advise consumers accordingly.

REACH regulations

Leather’s desirable properties, such as breathability, flexibility and long life, are enhanced by chemicals. However, are chemicals safe? The answer is it depends on the substance and how much of it one is exposed to.
The European Union (EU) is leading the world in making chemicals usage safer. The Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) entered into force on June 1, 2007. Its main aim is to ensure a high level of protection of human health and the environment from the risks that can be posed by chemicals8. It lays down provisions governing the manufacture, placing on the market and use of chemical substances and preparations. Chemical substances, which will be intentionally released, are also covered.  
Chemical makers have to demonstrate how the substance can be used safely and to communicate the risk management measures to users. The Biocidal Products Regulation (BPR) of May 22, 2012, has placed severe restrictions on the marketing and use of biocidal products9. All biocidal products require an authorisation before they can be placed on the market and their active substances must be previously approved. It is important that all tanneries and leathergoods manufacturers, as well as brands and retailers, comply with REACH and BPR, to protect the reputation of leather on a national and international scale.


Tanneries are a good example of a pioneer industry that recycles waste, producing a valuable product. However, the industry is not free from incorrect behaviour and the damage caused to its reputation by those few cannot be taken lightly. Social responsibility is becoming increasingly important. This refers not only to wages but also to working conditions.
Most tannery operations are performed using chemicals. The effects on workers and consumers are well known. Quality checks and control of unwanted substances are necessary to protect the consumer10. However, production is safe, chemicals are well-controlled and good-quality leather does no harm.
Nevertheless, tanneries constantly embark on innovation to improve protection of human health and the environment from the risks that can be caused by chemicals, while ensuring the competitiveness of the tanning industry. These must be considered in business, public and political debates: the leather industry is not a part of the problem but a part of the solution.

(1) Theodor Körner, Die Geschichte der Gerberei, Die Haut, Springer Verlag Volume 1/1 1944
(2)  Bernhard. Ramazzini, De Morbis Artificum Diatriba ("Diseases of Workers"), Modena 1700
(3) Johann Christian Gottlieb Ackermann, Abhandlung von den Krankheiten der Künstler und Handwerker, Stendal 1780
(4) Best Available Techniques (BAT) Refer­ence Document for the Tanning of Hides and Skins, European IPPC Bureau 2013
(5) Sicherheit und Gesundheit bei der Arbeit 2011, Bundesministerium für Arbeit und Soziales (BMAS), DE-10117 Berlin, ISBN 978-3-88261-731-3, 2013
(6) World Statistical Compendium for raw hides and skins, leather and leather footwear 1993-2012, FAO, 2013
(7) Globally Harmonized System of Classification and Labelling of Chemicals, Fifth revised edition, United Nations, 2013
(8) Regulation (EU) No 528/2012 concerning the making available on the market and use of biocidal products of 22 May 2012
(9) Regulation (EU) No. 2006/121 Registration, Evaluation, Authorisation and Restriction of Chemicals of 18 December 2006
(10) The International Union of Leather Technologists and Chemists Societies (IULTCS) official methods of analysis for leather, published by the International Organization for Standardization (ISO) CH-1211 Geneva
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