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Denim is a wardrobe staple for our customers and people around the world, and at M&S we sell one in every 10 pairs of jeans in the UK. However, the denim industry is considered being one of the most resource intensive parts of the fashion industry - known for high water use during manufacturing and being particularly chemical-intensive during dyeing and washing stages. At M&S, we recognise that denim manufacturing and garment washing has a huge amount of potential for improved resource efficiency and reduced environmental impact. We know our customers want style, quality and value with sustainability built in as standard. That’s why we’re doing our bit to make sure M&S jeans are made more sustainably for the future. 

In 2021, we launched our most sustainable denim range yet, using 100% responsibly sourced cotton and using 80% less water in the finishing process by partnering with Jeanologia – a leader in sustainable finishing technologies. We’ve also started to replace standard Indigo dyes with alternatives that are cleaner and more resource efficient dyestuff. 


We work with our suppliers to ensure all M&S branded denim garment are developed and manufactured according to our M&S Sustainable Denim Principles. These principles refer to the sustainable attributes and initiatives that M&S are applying in the manufacturing of denim garments, to reduce the impact on the environment through the use of best available technologies.  

The objectives for these principles are: 

  • To ensure M&S improves the environmental impact of its denim products 
  • To lay out a set of uniform principles around the development of denim product that will need to be adhered to by all business units consistently 
  • To measure the environmental impact score of every garment wash process
  • To ensure due diligence is undertaken with regards to the verification of fabric dyeing methods, garment wash processes and environmental impact scores
  • To ensure M&S can substantiate any marketing claims for products marketed as using sustainable denim 

These guiding principles set out that all denim products should be developed to 

  • Use responsibly sourced Cotton 
  • Reduce water usage in dyeing and garment washing
  • Utilise new technology and advances in chemistry 

Responsibly sourced Cotton 

Cotton is the main fibre used in denim fabrics. We are committed to ensuring that 100% of the cotton for our clothing continues to be responsibly sourced – a goal we first met in March 2019. We’ve identified more sustainable sources of cotton as meeting any of the following standards:  

  • Better Cotton Initiative (BCI) 
  • Fairtrade Certified 
  • Organic Cotton 
  • Recycled Cotton 

The majority of our cotton is sourced to BCI standards, with the remainder made up or organic, recycled or Faritrade cotton. 

All cotton fibre sourced for M&S denim products must be sourced according to the M&S Responsible Cotton Sourcing Policy.

Find out more about our approach to sourcing cotton.

Resource efficient dyeing 

Denim fabrics are yarn dyed using synthetic indigo dyes.  All wet processing facilities must operate in compliance with the M&S Environmental & Chemical Policy.  All chemicals used in the dyeing and finishing of raw materials for M&S must comply with the Manufacturing Restricted Substance list and relevant standards including UK & EU REACH. 

The process for dyeing denim fabrics uses high levels of water, energy and chemicals. Developments in chemistry mean that there are improved indigo dyestuffs on the market which significantly reduce dyeing time, water consumption and chemical use.  

M&S are committed to phasing out the use of standard powdered Indigo dyes, converting to Pre-reduced Indigo which is a cleaner and more resource efficient dyestuff – it requires less water, less hydrosulphite and less energy in the dyeing process. 

Garment processing 

After sewing, all denim garments are washed at an industrial laundry to give them a softer handle, adjust the colour level and apply fashion effects. These finishing processes can use high levels of water and involve labour intensive methods to distress garments.  

Innovative technologies and chemical advances mean that resource efficient wash processes are more widely available and can be applied to volume production. The laundries that we work with use the latest machinery with water saving devices that lower liquor ratios (water per kg garments). 

We are eliminating the use of Potassium Permanganate (PP) Spray which provides fashion fade effects. PP is linked to lung conditions in workers, following prolonged exposure. We’re replacing its use with either laser or lower impact chemical sprays, free of any heavy metals.  

The use of new technology has positive impacts on water and chemical use as well as reducing worker impact.  We are encouraging the adoption of hands-free laser processes in place of hand sanding, brushing and spraying. 

No improvement without measurement 

To standardise the assessment and measurement of the garment processing of our products, we use a measurement platform developed by Jeanologia called EIM – Environmental Impact Measurement. EIM is a standardised industry-wide system used to compare environmental impact data at washing level. This software measures impacts across four indicators: Water, Energy, Chemicals, Worker Impact.   

All laundries supplying to M&S are required to subscribe to EIM and undergo training and accreditation by Jeanologia. EIM scores are submitted by the laundry at development and bulk stage.  

To establish an EIM score, the laundry enters the wash process steps into the system. This includes details of each dry and wet process including water use, temperature, time and chemical dosing. Using an algorithm, the EIM score takes into account how the product is performing on the 4 indicators. A lower score indicates a lower environmental impact. A score of 33 or less is ranked “Green” or low impact. 

Use of the measurement tool offers complete transparency of the wash process steps and an opportunity to drive the adoption of more resource efficient washing. By deploying EIM we have reduced water usage by over 80%, compared to the industry average for garment finishing, according to Jeanologia. 

Future Steps 

In July 2021, M&S announced that we are participating in the Jeans Redesign project, collaborating with our partners at the Ellen MacArthur Foundation. The project works to guidelines which are a starting point for industry to design and make products aligned with the principles of a circular economy. Making jeans that are used more, made to be made again, and made from safe and recycled or renewable inputs.