Mass balance without guardrails becomes a risk. With guardrails, it can be a bridge.
By Annette Stube
Chief Sustainability Officer at the LEGO Group
This article was first published on edie and is republished here with permission. Read the original article here.
How do we transform the materials behind everyday products? For industries originally built on fossil-based plastics, progress towards non-fossil feedstocks isn't an easy switch.
At the LEGO Group, the question is especially important. LEGO® bricks are designed for children and to be passed from one generation to the next, meaning any new material must meet our high safety, quality, and durability standards.
As we recently shared in our 2025 Sustainability Report, we hit a significant milestone on our sustainable materials journey. In four years we have gone from having an estimated average of less than 2% of the materials we buy to make our bricks coming from renewable and recycled sources to over half (52%), largely made possible due to the mass balance approach. As such, less virgin fossil was needed to make LEGO® bricks in 2025 than in 2022, even as the company revenue grew 29% in the same period.
This progress however, is not just about us reaching our goals. It’s also about a willingness to work within imperfect systems with a commitment to improving them, whilst staying committed to sustained investment and long-term thinking that will help us change complex supply chains as we progress towards non-fossil feedstocks.
That’s why, in the near-term, the LEGO Group purchases ISCC PLUS certified mass balance resin and support the broader adoption of strong guidelines and definitions. Our expectations include clear rules for physical connectivity, where renewable and recycled inputs are part of the same production process and chemical connectivity, meaning we only buy feedstocks which have the same chemical components as those needed to make our products. We also ensure traceability through independent tracking and verification.
Scale needs to match integrity, and at the LEGO Group, we focus on what we can credibly claim. Mass balance certification lets us attribute renewable inputs to the materials we buy but it doesn’t mean any single brick contains a set percentage of those materials. Clarity matters, and that’s why clear, global guardrails are needed to define mass balance and uphold transparency around the approach. Without them, it is at risk of being diluted through misleading claims that can undermine credible progress.
We’re aiming to not only change what we make and sell but encourage a broader industry shift. Our ultimate ambition is to use renewable and recycled materials that are physically added to our products and we’ve seen success with innovations like artificial marble kitchen worktop offcuts, which are used in some of our transparent LEGO elements. But while we’re investing in technology that move us away from fossil content in the long-term, right now, the plastics industry is not ready for the system-wide sustainable transition needed to scale the materials that are critical to making the classic LEGO bricks which are found in most of our sets. The fact is, alternative materials and supporting infrastructure do exist for many single use plastics, but not for durable plastics at scale. We cannot compromise on safety or durability of the product, and scaling new materials responsibly takes time.
This is why we see mass balance as an important stepping stone on our journey to more sustainable materials, rather than the destination. It’s a practical bridge between reducing our purchases of virgin fossil-based feedstocks today while we work toward our long-term ambition to increase fully physical renewable and recycled material streams across the industry – not just our own.
We know there’s still a long way to go, but we’re pleased to be heading in the right direction. We want to play our part in building a more sustainable future for children – and we’re taking on this challenge with transparency and optimism.