Glutaraldehyde (GTA) is an aldehyde that can be used as an alternative to chrome tanning. In July 2021, it was listed on the SVHC (substances of very high concern) candidate list due to its respiratory sensitising properties.

This places certain obligations on suppliers of articles containing it at a concentration greater than 0.1% w/w (percent concentration of a material in solution) in that they have a responsibility to provide enough information to allow safe use of that article. Tanners producing wet-white, chrome-free and synthetically tanned leathers are among those most likely to be affected.

Some things in life come as a surprise. Many surprises, however, only occur to those who refuse to face reality. Thomas Lamparter from Wet-green GmbH in Reutlingen, Germany, can confirm that. He engages with many people in the leather industry including tanners, brand managers and designers. In some conversations, he says that he gets the distinct impression that the topic of GTA has seemingly fallen from the sky, surprising and threatening to disrupt the entire leather industry. There is a great commotion, outraged reactions and widespread consternation. While this may well be something of an exaggeration, he doubtless has a point. 

Indeed, he also notes that the German automotive manufacturer BMW has a firm grip on this reality. Several years ago, the company realised that sustainability, ‘Cradle to Cradle’, increasing supplier responsibility and general awareness of environmental and nature conservation concerns were not just passing media fads that would soon subside. Instead, these issues have steadily gained relevance in recent years. Year after year, brand communication is increasingly required to address these topics and provide reliable answers to a generation whose concerns revolve around the future of the planet. 

The usual response to such questions is to create smokescreens. Flowery promises are made and fantasies of the impossible are concocted, all in the hope that no one will bother to look behind the screens. But often, the truth behind them is bleak. This calculation is becoming less successful as consumers are reluctant to be taken for fools. How else can one understand it when manufacturers promote a ‘natural’ tanning agent that claims to use olive mill wastewater (OMW) as a significant substance but when analysed in the lab also includes the addition of glutaraldehyde? These claims and their promotion are essentially just ‘greenwashing’.

Sustainable alternative

However, Lamparter claims there has been a completely transparent, real and sustainable alternative available for over a decade in the form of wet-green OBE. A tanning agent developed by the German company Wet-green meets all the requirements of the modern leather industry and has nothing to hide. BMW was one of the first companies worldwide to explore this possibility beyond conventional chemical tanning agents. And has apparently met with great success. But it is not just the automotive industry that has caught on; the fashion industry is now using Olivenleder extensively. 

Renowned brands such as Hugo Boss, Alpha Tauri (Red Bull), Tricker's, Moral Code and Grenson have realised that leather cannot be treated as if advances in tannages have not been made. Patagonia, known for producing high-quality products that are both functional and durable, has been a pioneer brand in terms of sustainable practices and has a strong community of customers who support its philosophy. When developing its work boots, the company considered there was no alternative but to tan its choice of American bison hides with the patented OBE. Patagonia is a highly respected brand and where it goes, others follow. It is also worth pointing out that the Olivenleder patent has yet to be broken, so these brands’ faith would seem well placed.

What is OBE?

Wet-green says that its OBE (olivenblatt-extrakt) is the only vegetable tanning agent in the world which has two natural binding mechanisms by combining the best of two worlds, phenols and a natural cross-linker. It also says that availability is not a problem as using the leaves of the Mediterranean olive harvest only, it can accommodate more than 40% of global leather production. “By using other by-products such as the pomace (filter cake) and the olive mill wastewater (black water), there is the potential to convert global leather production to being tanned with by-products from olive growing for a real circular system,” claims Mr Lamparter.

An attractive feature of Olivenleder, besides its environmental credentials, is the variety of leathers it can produce. For example, whereas vegetable tanning normally results in a firm finished material, the OBE system can produce a variety of textures and colours, something that more and more brands are picking up on. The company claims that virtually any type of footwear can be produced, including casual sneakers, work boots and dress shoes. The only limitation so far is the hydrophobing for military grade leathers used for hiking boots which can be subjected to hours of water contact. The tanning agents present are the same as those found in some natural cosmetics and in extra virgin olive oil, and are designed to be neither corrosive nor a hazardous substance. 

Good all round properties

The colour possibilities for Olivenleder are said to be limitless and the leather just as soft as traditional conventional leathers. The substance of the olive tree that protects it, Oleuropein, takes on the task of glutaraldehyde, zeolites or other metals in the tannery, ensuring a soft and flexible bonding of the skin fibres. Lamparter says the complete ingredient list of this tanning agent would fit on the smallest note: Oleuropein. It is extracted from olive tree leaves, olive oil production residues and olive mill wastewater through a globally patented process which maintains its unbroken status.

Numerous awards from reputable institutes confirm that this tanning agent has the potential to be a sustainable and healthy game-changer. The USDA has awarded it the ‘100 percent Biobased/BioPreferred’ label and the German Dermatest seal confirms its ‘excellent’ skin compatibility. Wet-green says that the fact that it can already meet over 40 percent of the global leather demand by using only the leaves from olive growing is yet another reason why tanners and their shoemaking customers have no need to take risks in the future. Consumers will appreciate being able to afford the luxury of sustainability in a completely transparent manner for a more sustainable and circular future of leather, without headaches.

White sneaker by Moral Code shows that contrary to some claims, Olivenleder can be used to produce white leather.
CREDIT: MORAL CODE

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