Published on 1 November 2024; updated on 3 March 2025 (stylistic edits); 24 April 2025 (expanded chemical breakdown and further reading section); 29 April 2025 (footnotes added)
Being vegan means embracing both animal welfare and environmental responsibility. Therefore, in the Material on Trial series, we explore the pros and cons of popular materials in the vegan fashion industry, giving each argument a fair hearing. Our goal is to better understand these materials, striving to minimise harm with every fashion choice we make, while celebrating solutions and innovations that bring us closer to a more sustainable future.
In this article, we focus on polyurethane (PU) leather, examining it both as a standalone material and as a component in plant- and mushroom-based alternatives, which may feature PU-coated backing or water-based PU resin finishes.
And so it begins…
Polyurethane (PU) was invented in 1937 by Otto Bayer and his team at IG Farben, Germany. However, it was not until the 1960s that PU found its way into the fashion industry with the introduction of DuPont’s Spandex (also known as Lycra). This revolutionised intimate apparel, swimwear, and athletic wear. PU leather also began to be used for bags and accessories during this decade as a cost-effective alternative to genuine leather, long before cutting down on animal-derived fabrics came into the spotlight.
Compared to PVC leather (polyvinyl chloride), PU leather has more fashion-friendly qualities, such as breathability and a supple feel, making a bag or jacket comfortable to carry, touch, and wear. These qualities have earned PU leather a pretty big following in vegan fashion, establishing it as ‘the vegan leather’ most vegan fashion brands utilise. Rising concerns about the environment and animal welfare are driving the global vegan leather market’s projected growth from USD 41.73 billion in 2024 to USD 88.06 billion by 20351.
However, as noble as this sounds, PU vegan leather is still derived from non-renewable fossil fuels, and does present difficult questions around sustainability and environmental impact versus animal-welfare concerns.
What makes PU leather a champ?
The primary argument for PU leather focuses on sustainability, defined by its lower resource requirements and, therefore, reduced environmental impact compared to both PVC leather and animal leather. Modern PU leather manufacturing utilises water-based processes that emit fewer hazardous chemicals than PVC production. This is precisely why PU leather has become a key player in both vegan and synthetic leather markets, even though PVC leather continues to maintain its position in niche sectors such as protective wear, where superior chemical and abrasion resistance outweigh sustainability considerations.
PU leather is essentially polyurethane resin laminated onto a sheet of fabric (polyester, cotton, nylon or rayon), which, unlike animal leather, does not require tanning or deforestation to graze the raw input. Animal leather production involves raising livestock, which consumes vast amounts of water, land, and feed. Cattle are raised for approximately 18 months before slaughter. The leather tanning, dyeing, and finishing process then takes six to eight weeks.
With the leather industry is estimated to have slaughtered around 430 million cows annually by 20252, the global feed requirement is approximately three trillion kilograms per year. Growing and transporting this amount of feed alone requires significant agricultural land, water consumption, energy, fertilisers, and pesticide use, which, over time, degrades soil health, reducing its ability to sequester carbon and support plant growth.
Deforestation for cattle grazing accounts for up to 80% of all deforestation in the Amazon rainforest. Globally, the leather industry consumes an estimated 400 billion litres of water annually, both for raising cattle and the water-intensive processes involved in tanning and finishing leather.
Most animal leather is tanned using hazardous chemicals. The tanning proces releases chromium compounds, synthetic tannins, biocides, dyes, and other chemicals including formaldehyde, glutaraldehyde, anthracene, arsenic, and heavy oils—into the environment. According to Collective Fashion Justice, producing a typical pair of cowhide leather boots emits at least 66 kg of CO₂, equivalent to charging 8.417 smartphones3. The carbon footprint issue extends further, as every time a cattle breathes, passes gas, and burps, methane is released—a greenhouse gas 25 times more potent than carbon dioxide. The FAO estimates that cattle rearing is responsible for 14,5% of annual emissions4.
And so, even though PU leather production does generate greenhouse gas emissions due to its petroleum-based origins, recent studies indicate that its environmental impact is about 33–50% less per square metra than that of animal leather. he carbon footprint alone is 15,8 kg per square metre for the entire supply chain of PU leather, compared to 17,0 kg (excluding emissions from cattle farming) and 110,0 kg (including emissions from cattle farming) per square metre of cowhide leather.56.
The second argument is that, as a synthetic material, the production of PU leather is more streamlined and vertically aligned of animal leather. Vertical integration allows efficient communication and quality control across all stages, which has been identified as a key factor enabling the implementation of innovations. The production of PU leather takes place in a controlled environment and involves fewer steps and less complexity than processing animal hides. In this case, fewer steps equals less waste, and allow for precise control over the amount of material used.
The production of PU leather involves several key chemicals that can be listed in one short paragraph. Polyols and isocyanates (MDI or TDI) create the PU structure; solvents such as dimethylformamide (DMF) and methyl ethyl ketone (MEK) dissolve the PU for application to a fabric base; catalysts and surfactants enhance overall efficiency; and additives like stabilisers, plasticisers, and colorants improve the material’s properties and appearance. Although these chemicals all have environmental impacts, they are generally considered less hazardous and have lower toxicity levels than the chromium salts used in the tanning process of animal leather alone.
So…what’s the problem?
On the other hand, the primary argument against the sustainability of PU leather centres on its durability. Even the most robust and high-quality PU leather wears down faster than animal leather, and as a result, consumers end up buying more products than they would if they picked animal leather in the first place. Overproduction is never sustainable.
To quote Angela Winkle, the chief sustainability officer at R. M. Williams, which owns Natural Fiber Welding, lower initial environmental footprints will be completely compromised if brands ‘have to make more products and consumers have to buy more products because the materials don’t last as long’. Although the durability of PU leather varies depending on its quality and composition, it is typically said to last three to five years of use7. Improving these odds often requires adding more chemical substances, which basically undermines the sustainability claims that PU leather seeks to uphold.
Another critical argument against PU leather is that it is, at its core, ‘just plastic’ – and while the status of polyurethane varies from source to source, most polyurethane manufactures do not classify it as plastic due to its distinctive structure, production, and properties as opposed to PVC, polyester (PL), polyethylene (PE) and acrylic (polymethyl methacrylate, or PMMA), just to name out a few. Still, both polyurethane and plastic are synthetic polymers, and such, not biodegradable at all. This is why both PU and PVC leather are commonly referred to as ‘pleather,’ short for ‘plastic leather’, as s confusing as this is.
Disposal is an issue that cannot be overlooked when it comes to polyurethane and petroleum-based synthetics in general. Depending on the specific formulation of PU leather, incineration can release several toxic chemicals, including isocyanates, nitrogen oxides, carbon monoxide, hydrogen cyanide, and volatile organic compounds (VOCs). Carbon monoxide, produced through incomplete combustion, is lethal—and so is hydrogen cyanide. Other substances can cause a range of serious health issues, from respiratory, skin, and eye irritation to isocyanate-induced asthma.
Once PU leather cracks and peels and is disposed of without incineration, it inevitably ends up in landfill, regardless of how many times – if ever – it has been successfully recycled. Wastewater, wind, rain, and floods then carry it – just as they do plastic, regardless of classification, along with any other transportable waste – from the land into the seas and, ultimately, the oceans.
An estimated 12 million metric tonnes of plastic enter the oceans each year. There are now more than 171 trillion pieces of plastic floating in the world’s oceans, a staggering increase from just 16 trillion in 2005. This debris breaks down into smaller fragments, namely microplastics and nanoplastics, which are ingested by marine organisms, from tiny plankton to large fish and birds. This leads to both physical harm and chemical contamination, affecting entire ecosystems. The problem extends beyond aquatic life; terrestrial life is also impacted as well. The accumulation of microplastics contaminates freshwater systems, alters the physical and chemical properties of the soil, and ultimately disturbs plant growth and soil health.
Humans ingest microplastics through food and water or inhale them directly from the air. Research has found microplastics in various human organs, including the liver, kidneys, lungs, placenta, and even the brain. Microplastics can contain harmful chemicals like BPA, phthalates, and PFAS, which can mimic human hormones and disrupt endocrine functions. These disruptions have been linked to fertility issues, impaired foetal development, and an increased risk of various types of cancer.
On second, or actually, third thought
The discourse on microplastics and their disastrous effects on ecosystems often overlooks the fact that these particles accumulate from all types of synthetics—including PVC—which emits harmful substances like phthalates and dioxins, as well as polyethylene and polyester, not just
polyurethane. Therefore, attributing the accumulated damage solely to
polyurethane while ignoring its relative sustainability compared to PVC and animal leathers is misleading at best.
While the involvement of numerous chemicals is frequently cited as a major drawback of PU leather in the ‘synthetic vs. natural’ debate, mainstream discussions often omit the very fact that PU leather production generally involves more sustainable and technologically advanced practices. Modern manufacturing techniques for PU leather are more efficient and can be scaled up with less environmental impact.
As companies control every stage of production, from raw material sourcing to final manufacturing, some types of PU leather are designed to be more easily recyclable, or even made directly from recycled materials. This contributes to a more circular economy, arguably the most significant shift in the sustainability discourse within fashion over the last decade. For example, bio-based polyurethane (bio-PU) is made using polyols derived from renewable biological sources such as vegetable oils — including soybean, castor, and rapeseed — rather than traditional petroleum-based feedstocks. This makes bio-PU a more sustainable alternative to conventional polyurethane, with potential advantages such as reduced reliance on fossil fuels and, in some formulations, enhanced biodegradability.
By contrast, animal leather tanneries have largely relocated to the Global South, where environmental regulations are more relaxed, and workers’ rights less protected. Despite some significant progress towards more environmentally friendly tanning processes – like vegetable tanning – chrome tanning remains the most widely used method, and accounts for about 758–90%9 of animal leather production. This is largely because chemicals used in chrome tanning are both relatively inexpensive and require less labour and time to apply and process, making tanning more cost-effective for large-scale production.
Substances used in chromium tanning are toxic, with some even classified as carcinogenic, causing serious health issues that affect the eyes, lungs, liver, kidneys, skin, and lymphatic system. Improperly managed chromium salts—particularly chromium VI—are known to cause severe respiratory problems, skin irritation, allergic reactions, and even cancer. Chemical waste seeps into local water sources, soil, and air, affecting entire ecosystems—humans included.
Last, but definitely not least
While we have extensively covered the sustainability claims of PU leather, centred on three main arguments: reduced resource requirements for production, advanced and streamlined manufacturing processes, and greater control over input and waste management, there are two additional yet fundamental points to add to the case.
From a manufacturer’s and a designer’s perspective, PU leather is one of the most versatile materials available. It can be crafted to replicate various textures and finishes, dyed in any colour or shade, and still remains more cost-effective than animal leather, making it accessible to a broader range of products and consumers alike.
Crucially, no animals are harmed in the production and development of PU leather. With advancements in manufacturing technologies, the impact on animal life and surrounding communities is minimised—an advantage that neither PVC nor animal leather can even begin to compete with.
…on a side note
Although the release of chemicals post-treatment depends on the environmental regulations of the manufacturing location, PU leather producers have significant control over their environmental impact. They have multiple opportunities to optimise sustainability solutions, which can be regulated and verified through sustainability procedures and third-party certifications. The certification of synthetic leather production—more streamlined than that of animal leather—emphasises chemical safety and environmental impact.
To uphold sustainability and ethical sourcing claims, manufacturers should ensure their management systems comply with ISO 14001 and ISO 9001 standards. The sustainability of a fabric or end product should also be validated through respected certifications such as Cradle to Cradle Certified™, while vegan claims should be certified by a reputable body such as The Vegan Society or EVE Vegan. Although third-party certifications can be costly, they are a worthwhile investment, enhancing a brand’s credibility in both B2B and B2C markets.
With the Greenwashing Directive set to become part of EU Member States’ national legislations, it is hoped that only PU leather with a verified minimal environmental impact will remain on the market.
By comparison, animal leather production system requires more extensive and varied certifications due to the complexities of its processing methods and the ethical concerns involved.
Verdict
Upon careful consideration of the arguments presented, is is acknowledged that the significant ethical advantage of PU leather lies in preventing animal harm. While its production generally requires fewer resources than animal leather, environmental concerns—particularly its non-biodegradability and durability issues—remain significant drawbacks that may deter environmentally conscious consumers, whether vegan or not.
Bottomline
Overall, PU leather is favoured for its alignment with vegan principles and animal welfare. However, it is strongly recommended that research and development continue into more sustainable and durable alternatives, such as plastic-free leather innovations, to address PU leather’s environmental limitations.
That’s it.
Further reading (in alphabetical order):
http://www.enveurope.springeropen.com/articles/10.1186/s12302-022-00689-x
http://www.custompolyurethane.co.uk/blog/is-polyurethane-a-plastic/
http://www.gallaghercorp.com/urethane-vs-plastic/
http://www.gianeco.com/en/faq-detail/1/55/polyurethane-is-plastic-
http://www.knowledgecenter.mearthane.com/polyurethane-vs.-plastic
http://www.kth.diva-portal.org/smash/get/diva2:1886097/FULLTEXT01.pdf
http://www.newtecoat.com/understanding-why-polyurethane-is-plastic-a-comprehensive-guide/
http://www.pmc.ncbi.nlm.nih.gov/articles/PMC7464512/
http://www.volatilefree.com/is-polyurethane-rubber-or-plastic
Footnotes
- For more growth predictions, download the Vegan Fashion Repository – Vegan Fashion Playbook 2024-2025; data after Statista, Grand View Research, Future Market Insights et varia ↩︎
- https://www.theguardian.com ↩︎
- https://www.collectivefashionjustice.org ↩︎
- https://www.fao.org ↩︎
- https://www.collectivefashionjustice.org ↩︎
- https://leatherpanel.org ↩︎
- https://laticoleathers.com ↩︎
- https://www.syncsci.com/journal/MER/article/download/MER.2021.01.004/511/ ↩︎
- https://slowfashionmovement.medium.com ↩︎