LEGO’s 52% Renewable Materials Milestone: What It Means for Businesses

LEGO tackles fossil plastics with controversial mass balance method

The LEGO Group has committed to replacing all virgin fossil plastics in its bricks by 2032. However, the company’s main tool for hitting interim targets relies on a method that critics say obscures what’s actually inside each product. Mass balance accounting lets LEGO claim renewable and recycled content by purchasing mixed resins from suppliers who blend fossil and non-fossil feedstocks. The company then attributes sustainability credits based on certified proportions, rather than tracking physical materials into finished bricks.

This approach has allowed rapid progress. In 2025, LEGO reported that 52% of its resin carried renewable or recycled attribution, up from 33% the previous year. Yet the same method faces growing scrutiny from regulators and campaigners who question whether it delivers genuine environmental improvement or simply provides convenient accounting.

For UK businesses watching this debate, the stakes extend beyond toy manufacturing. Mass balance claims are spreading across supply chains, from packaging to chemicals. Understanding how they work, where they’re regulated, and what risks they carry matters for anyone making sustainability commitments to customers or reporting progress to stakeholders.

How mass balance accounting works in practice

Traditional plastics production relies on petroleum-based resins. LEGO bricks have historically used acrylonitrile butadiene styrene, or ABS, derived entirely from fossil sources. Replacing this material physically requires either bio-based alternatives like sugarcane polyethylene or recycled plastics recovered from waste streams.

Both options face constraints. Bio-plastics remain expensive and limited in supply. Recycled plastics make up less than 5% of global production and often lack the consistency needed for precision manufacturing. LEGO tested over 600 alternative materials but found few that met its quality standards at scale.

Mass balance sidesteps these bottlenecks. Suppliers blend renewable inputs such as used cooking oil or plant-based feedstocks with fossil resins in their production systems. The mixed output gets certified by third-party schemes like ISCC Plus, which verify the proportion of non-fossil content. LEGO then purchases this certified resin and attributes the sustainability percentage across its product lines, even though individual bricks may contain only fossil-derived plastic.

The company pays up to 70% more for mass balance resin than conventional alternatives, according to CEO Niels Christiansen. This premium helps suppliers invest in renewable feedstock processing and scale up production capacity. For LEGO, it provides a route to reduce fossil dependency while maintaining the durability and precision its products require.

LEGO’s timeline shows accelerating adoption

Progress has been swift. In 2023, mass balance resin made up 18% of LEGO’s total, translating to roughly 12% attributed renewable or recycled content in finished products. By mid-2024, that figure reached 30% of resin and 22% of product content. The company also introduced bio-polyethylene in over 200 botanical sets and minifigure accessories during this period.

Full-year 2024 results showed further gains. Mass balance resin hit 47% of total volume, with 33% attributed content across the product range. The latest figures for 2025 report 60% mass balance resin and 52% attributed content, including 4% from directly sourced sustainable materials that are physically traceable.

These increases put LEGO ahead of its interim target to halve virgin fossil plastic use by 2026. The company’s Chief Operating Officer, Carsten Rasmussen, stated that investment in supply chain infrastructure has been central to this progress. LEGO continues to expand its network of certified suppliers while testing additional materials for physical incorporation.

Nevertheless, mass balance remains the dominant tool. The company describes it as a transitional method, necessary until renewable and recycled feedstocks become widely available at the quality and volume needed for full physical replacement.

Regulatory and public pressure tests transparency claims

Not everyone accepts this logic. Beyond Plastics, a US-based campaign group, compared mass balance to “putting one almond in a cake and calling it an almond cake.” The criticism centres on traceability. Consumers cannot verify whether any given brick contains renewable material or remains entirely fossil-based. Attribution happens at the accounting level, not the physical product.

Regulatory action has followed. In 2024, the US Environmental Protection Agency barred mass balance claims under its Safer Choice label for household cleaning products. The agency concluded that such claims could mislead consumers about the actual environmental benefit of individual items. This decision signals growing scepticism among authorities about accounting-based sustainability methods.

LEGO’s Chief Sustainability Officer, Annette Stube, acknowledged the risks in a recent interview. She argued that third-party certification provides necessary guardrails, preventing mass balance from becoming a vehicle for greenwashing. According to Stube, the method works as a bridge when applied transparently within industries dependent on fossil feedstocks. Without those safeguards, she warned, it becomes a risk to credibility.

The debate mirrors wider tensions in corporate sustainability reporting. Many companies now publish detailed carbon accounting and material sourcing data. However, stakeholders increasingly demand proof of physical change, not just attributed improvement. For businesses relying on supply chain adjustments rather than direct material substitution, this shift creates reputational and regulatory exposure.

What mass balance means for UK manufacturers and suppliers

UK businesses face similar pressures across multiple sectors. Food producers use mass balance for palm oil and cocoa sourcing. Chemical manufacturers apply it to bio-based solvents and polymers. Packaging suppliers rely on it for recycled content claims when physical separation proves uneconomical.

The method offers commercial advantages. It costs less than full physical traceability and lets companies scale renewable purchasing faster than supply chains can deliver segregated materials. For organisations with aggressive sustainability targets, mass balance provides a route to report progress without waiting for technology or infrastructure to catch up.

However, the risks are mounting. Customers and regulators now scrutinise sustainability claims more closely, particularly where attribution replaces physical content. Companies using mass balance must be prepared to explain the difference clearly and defend their approach against accusations of greenwashing. Those that fail to communicate transparently may face reputational damage or regulatory sanction.

Supply chain implications also matter. Mass balance works only when upstream suppliers adopt certified systems and pass costs downstream. UK manufacturers buying certified materials pay premiums similar to LEGO’s experience. These costs must be absorbed, passed to customers, or offset through efficiency gains elsewhere. Smaller businesses may struggle to afford participation, creating competitive disparities.

The public sector adds another layer. Procurement frameworks increasingly require evidence of sustainable sourcing. Mass balance claims may not satisfy buyers demanding physical recycled content or bio-based materials. Suppliers relying on attribution could find themselves excluded from tenders unless they supplement mass balance with traceable alternatives.

Compliance obligations are also shifting. While UK regulations do not yet restrict mass balance claims explicitly, the EPA decision in the US suggests that future rules may require clearer labelling. Businesses should monitor guidance from the Competition and Markets Authority and the Advertising Standards Authority, both of which have issued warnings about vague environmental claims.

Key facts about LEGO’s mass balance approach

• LEGO reported 52% attributed renewable or recycled content in 2025, up from 12% in 2023, primarily through mass balance resin purchases.
• The company pays up to 70% more for mass balance certified resin compared to conventional fossil-based alternatives.
• Mass balance allows suppliers to blend renewable feedstocks with fossil plastics and attribute sustainability credits based on certified proportions, rather than physical tracking.
• Third-party certification schemes like ISCC Plus verify the proportion of non-fossil content in mixed resin batches.
• LEGO aims to eliminate all virgin fossil plastics by 2032, with an interim target of halving use by 2026.
• Critics argue mass balance obscures actual material content, while the US EPA barred such claims under its Safer Choice label in 2024.
• LEGO describes mass balance as a transitional tool, continuing to invest in physically traceable renewable and recycled materials.

How businesses should approach mass balance decisions

Companies considering mass balance need to weigh speed against transparency. The method enables faster progress toward sustainability targets than waiting for fully traceable alternatives. For organisations with public commitments or supply chain pressure, this timing advantage can be significant. However, it comes with communication responsibilities.

Clear disclosure matters most. Businesses should explain what mass balance means and how it differs from physical content replacement. Marketing claims must avoid implying that every product contains renewable or recycled material if attribution only happens at portfolio level. Transparency builds trust and reduces the risk of regulatory or reputational backlash.

Certification provides some protection but does not eliminate scrutiny. Third-party schemes verify supplier data and ensure chain of custody, but they do not address the fundamental question of whether attributed content equals real environmental benefit. Companies should treat certification as a minimum standard, not a shield against criticism.

Combining mass balance with physical alternatives strengthens credibility. LEGO’s approach includes both attributed resin and directly sourced bio-plastics in specific product lines. This blend demonstrates genuine investment in material innovation while using mass balance to scale interim progress. UK businesses can adopt similar strategies, reserving traceable materials for customer-facing applications where transparency matters most.

Long-term planning should assume tighter rules. The regulatory environment is moving toward stricter definitions of recycled and renewable content. Businesses relying entirely on mass balance may need to pivot as standards evolve. Building supplier relationships that support both attributed and physical traceability provides flexibility for future compliance.

Financial planning must account for premium costs. Mass balance resin and certified feedstocks cost significantly more than conventional materials. These expenses affect margins, pricing, and competitiveness. Companies should model cost scenarios and consider how to communicate value to customers willing to pay for sustainability, while managing pressure from those who are not.

Finally, businesses should prepare for stakeholder questions. Investors, customers, and employees increasingly ask detailed questions about sustainability claims. Organisations using mass balance need clear, consistent responses that acknowledge both its benefits and limitations. Avoiding defensiveness and engaging honestly with concerns builds credibility and reduces the risk of being dismissed as greenwashing.

Where to find authoritative guidance and resources

The UK government provides information on waste and resource management through the Department for Environment, Food and Rural Affairs, including guidance on recycled content and circular economy policy. Businesses can also consult the Competition and Markets Authority’s Green Claims Code, which sets out rules for environmental marketing to avoid misleading consumers.

For sector-specific standards, the British Standards Institution publishes technical specifications on recycled materials and sustainability reporting. The Institute of Environmental Management and Assessment offers professional guidance on environmental compliance and best practice for UK businesses.

Companies pursuing carbon reporting compliance and net zero commitments may benefit from structured support that integrates material sourcing with broader emissions reduction strategies. Understanding how supply chain choices affect Scope 3 emissions helps organisations make informed decisions about mass balance and alternative materials.

Those looking to build internal capability on sustainability topics can explore training resources focused on environmental management and reporting, which help teams navigate complex sourcing decisions and communicate progress effectively to stakeholders.