Leather

Leather is a material obtained through a complex process of transforming animal skin, called tanning, which makes it rot-proof, durable, and resistant over time.

By definition, only this transformation makes it possible to refer to “leather”: synthetic or textile materials cannot bear this designation, which is strictly regulated. 1

• Fiber type : Natural animal material mainly derived from cattle, sheep and goat hides and skins, but also from exotic skins (ostriches or reptiles such as crocodiles, snakes, lizards, iguanas), and fish skins.
• Status : Leather is considered a co-product of the agri-food industry, derived from livestock farming and slaughter for meat and milk, and subsequently recovered through a transformation process (cattle, calves, sheep, goats, pigs). Leathers from species other than those traditionally used in leather goods are considered exotic leathers. This is the case for reptiles (crocodiles, alligators, caimans, pythons, lizards), fish (shagreen, salmon, sturgeon, eels) and birds such as ostriches. For certain exotic leathers (crocodilians, lizards, pythons, ostriches), trade is strictly regulated by the CITES Convention 2, which imposes traceability rules, quotas and controls on farming and harvesting in the wild. Skins from species threatened with extinction remain prohibited from international trade and are illegal.
• Global leather production : Measured in raw hides and skins from cattle, sheep, goats and buffalo, it is estimated at 13.8 million tons in 2024 3. Cattle hides are the most commonly used type of hide or skin (68%), followed by sheep skins (16%), then goat skins (10%) and buffalo hides (5.7%) 4. Exotic leathers account for less than 1% of global leather production. There is no single institutional statistic, as these supply chains are fragmented and only certain species are systematically monitored, notably through CITES. For example, the global crocodilian market was estimated at 1.3 million skins in 2023 5, mainly from farming.

• Main raw hides and skins producing countries (FAO, 2024) 6 :
  - China : 21,98%
  - India : 11,55%
  - United States : 8,61%
  - Brazil : 8,01%
  - Pakistan : 4,09% 
• Main raw cattle hides producing countries (FAO, 2024) :
  - China : 19%
  - United States : 14%
  - Brazil : 13%
  - Argentina : 6%
  - Australia : 4% 

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Leather is a natural material valued because it is both strong, supple and comfortable. It offers good resistance to wear and tear (tensile stress, tearing, flexing) 8, can last for many years and remains pleasant to wear.

The properties of leather can therefore be highly diverse and vary depending on the type of tanning used and the finishes applied. Thanks to these properties, it is found in many everyday items: shoes, bags, clothing, furnishings or transport, where durability, comfort and aesthetics are all sought after.

Stages of the production process

Tanning processes :

1. Mineral tanning, pmainly carried out with chromium salts, accounts for more than 80% of global production 12. It is performed by soaking hides and skins in drums and has the advantage of being particularly fast, requiring only a few hours to a few days. This method produces supple, lightweight and highly resistant leathers, which explains its widespread use in the footwear, leather goods, clothing and furnishings sectors. At the end of the treatment, the leather obtained is called wet blue because of its characteristic bluish colour and can be sold before the retanning, dyeing and finishing operations. Its main advantage lies in its industrial efficiency and in the mechanical properties of the leather obtained (suppleness and resistance), making it particularly suitable for large-scale production. However, the use of chromium salts raises environmental and health concerns, particularly regarding effluent treatment and the management of tannery waste.

2. Plant tanning is an older method using natural tannins extracted from bark, leaves or roots. It accounts for around 20% of global tanned leather production 13. The process consists of immersing hides and skins in vats rich in tannins for several days, or even several months. Its main advantage lies in the use of renewable raw materials as well as in the natural and authentic appearance of the leather obtained, which is valued in high-end leather goods and craftsmanship. Nevertheless, this process is longer, more costly and less suited to mass production. The leathers obtained are generally firmer and less supple than those produced through mineral tanning. They are mainly used to make soles, saddles, belts, shoulder straps and bag handles, waist belts and in furnishings.

3. Synthetic tanning is based on the use of synthetic tanning agents, called syntans, chemically produced from organic compounds such as phenols or sulphonated naphthalenes. Developed in the early 20th century to supplement or replace certain natural tannins, they can be used alone or in combination with chrome or plant tanning during retanning operations. Its main advantage is its great flexibility: it makes it possible to obtain, relatively quickly, highly homogeneous, lighter-coloured leathers (synthetically tanned leather is called wet white), which are more supple, have good light resistance, and make dyeing easier. Conversely, it relies on the use of synthetic chemical compounds that generate effluents requiring specific treatment. It is therefore less valued by consumers seeking natural processes. It is mainly used for leathers intended for clothing, soft leather goods and furnishings, when specific aesthetic or technical performance characteristics are required 14.

Production diagramn

Environmental issues of production

The environmental impact of leather is mainly linked to the farming of the animals from which the hides and skins are derived, and to the transformation processes, particularly tanning.

The transformation of hides and skins is the second main area of environmental concern. Tanning, dyeing and finishing opérations consume water, energy and numerous chemical products.

Thus, the main areas of concern in the leather sector relate to greenhouse gas emissions linked to livestock farming, pressures on soil, water and biodiversity, as well as the control of pollution and resource consumption associated with tanning and finishing operations.

1. Durability

Leather is often presented as a durable material because of its long service life. Products made from high-quality leather, particularly full-grain leathers, can remain functional for several decades when they are designed to be repaired and reused.

This longevity is now taken into account in certain environmental assessment methodologies for materials 21. Indeed, when a product is used for many years, the impacts associated with its manufacture are spread over a longer period of use.

However, the durability of leather varies significantly depending on its quality, manufacturing method and use. Full-grain leathers and certain vegetable-tanned leathers generally offer better resistance to ageing and repair than corrected or heavily pigmented leathers. The actual service life of an item also depends on its exposure to mechanical stresses, its use and the quality of its design. There is therefore no single service life for leather, but a wide range of performance levels depending on the products considered 22.

2. Recyclability

The manufacturing of leather products generates significant quantities of solid waste throughout the transformation chain. For example, during the manufacture of footwear and leather goods, it is estimated that 20 to 30% of finished leather becomes cutting scraps 23. Only part of these scraps is transformed into new materials; the rest is recovered for other uses or disposed of. Leather recyclability remains possible but relatively complex. There are several ways to recover leather waste 24:

• Upcycling or reconditioned leather consists of recovering leather from a product in order to reuse it as it is and give it a second life, without changing its composition.
• Bonded leather 25(regenerated or reconstituted leather) is made by recovering leather and leather scraps from tanneries or production workshops, which are then ground and mixed with other composite materials such as latex to create a paste. This paste is then dried and rolled out into a thin layer to recreate usable material from leather waste that would usually be discarded.

The recovery of leather at end of life remains limited today by several technical constraints. Leather products are often combined with other materials (textiles, foams, rubber, metal) or covered with coatings and surface finishes that make their identification, sorting and recycling more difficult. In the case of footwear in particular, the diversity of components makes dismantling and material separation especially complex. Furthermore, chrome tanning, which is widely used in the industry, can limit certain recycling routes because it requires specific precautions to avoid the formation of toxic compounds during thermal treatments. Coatings and surface treatments can also degrade the quality of the recycled material. In this context, despite the development of new sorting and recycling technologies, recovery solutions remain limited and require further research and development efforts. The sector therefore currently prioritises an approach based primarily on durability, repair, reuse and extending product lifespans, complemented by the gradual development of recycling and recovery solutions within a circular economy approach.

Footwear generally contains regulatory pictograms informing consumers about the composition of the three main parts of the shoe (upper, lining and outsole). Predominant materials such as leather must therefore be clearly indicated as shown below 26:

27 Alternative materials to leather :

There are now many alternatives to leather, which may be of synthetic or plant-based origin. These materials address different issues, such as reducing the use of animal resources, textile innovation or waste recovery. However, they cover very diverse realities in terms of composition and impact.

Plastic materials, often called faux leather or “leather-like” materials, are the oldest and most widespread alternatives. They are generally made from polymers such as polyurethane (PU) or polyvinyl chloride (PVC), derived from petroleum, and designed to imitate the appearance of leather. Produced on a very large scale and widely integrated into global supply chains, they benefit from established industrial infrastructure and relatively low production costs. Their industrial maturity is therefore considered very high, with global availability. Although these materials have the advantage of being less costly and offering an alternative to traditional leather, they also raise serious environmental issues: they generate significant plastic waste as well as polluting emissions during their production and at end of life 28.

Finally, alternatives grouped under the term plant-based or bio-based materials are developing rapidly. They can be produced from agricultural waste (pineapple fibres, apple or grape residues), fungi (mycelium), bacteria or cork 29. These materials aim to reduce dependence on animal-based resources and recover certain agricultural co-products, while offering an appearance similar to leather. For example, pineapple-fibre textile uses fibres from leaves derived from agriculture, while mycelium is cultivated to create a supple and biodegradable material. However, their level of industrial maturity remains variable, and many are still produced on a small or medium scale. Furthermore, it is important to note that many of these alternatives still incorporate synthetic binders, coatings or backings to improve their durability, which limits their recyclability. Although they represent interesting avenues for innovation, these alternatives still struggle to match leather in terms of resistance, repairability and service life 30. Their real environmental performance therefore depends heavily on the manufacturing processes, their composition, but above all on their duration of use and therefore their resistance.

Existing labels and certifications :

The certifications applicable to leather are key reference points for identifying more responsible practices. They enable companies and consumers to better guide their choices. The Leather Working Group (LWG) 31, certification, the most widespread in the leather industry, is based on a system of environmental audits of tanneries. In particular, it assesses water and energy management, effluent and waste treatment, atmospheric emissions, supply traceability, as well as the management of chemicals used throughout the manufacturing process.

The OEKO-TEX Leather Standard focuses on the safety of finished products. It certifies that leathers have been tested for harmful substances at each stage of production, according to strict scientific criteria.

Other more local certifications, such as ICEC in Italy, also contribute to traceability and to the control of inputs and processes in tanneries.