A new framework published by BB-REG-NET proposes seven additional impact categories for Life Cycle Assessment to address what researchers describe as inherent bias against bio-based chemicals and materials in current sustainability standards.

The report, Seven Steps to Fairness, identifies that standard LCA methods were developed when fossil-based materials were the established norm. Survey data from BB-REG-NET finds that while 95 per cent of bio-based sector businesses recognise the importance of LCA, 67 per cent believe current standards favour fossil materials, and 83 per cent consider current regulations unsatisfactory.

The report proposes that comparative LCA studies assess seven additional impact categories alongside existing methods: biodegradability, bioaccumulation, persistence, microplastic formation, biodiversity impact, litter, and biogenic global warming potential. This framework aims to capture environmental characteristics relevant to bio-based materials that existing impact assessment methods do not measure.

"The issue is not that LCA is wrong, but that it is incomplete," said Stuart Walker, lead author from the University of Sheffield. "Many of the impact categories used today were designed around fossil-based systems, meaning bio-based materials are compared on an uneven playing field."

Impact categories and end-of-life treatment

Standard LCA impact assessment methods such as ReCiPe and Environmental Footprint include approximately 16 to 18 midpoint indicators covering areas including climate change, acidification, and ecotoxicity. The BB-REG-NET report argues these categories were consolidated when fossil-based materials were often the only viable option for a product, leading to frameworks that do not capture the potential advantages of bio-based alternatives.

The report identifies particular challenges around end-of-life treatment modelling. A compostable material designed for industrial composting may be assessed under default scenarios such as incineration because approved composting models are not available within standard frameworks. This affects how biogenic carbon is treated in the assessment: if a compostable bio-based material is modelled as incinerated, biogenic carbon is calculated as immediately emitted as CO₂, whereas composting may result in partial carbon retention in soil.

Dr Jen Vanderhoven, Chief Executive Officer of the BBIA and contributing author, said: "If we want businesses to transition away from fossil-based materials, the tools used to judge sustainability must evolve as well. Transparent, balanced LCA methodologies are not just a technical issue – they directly shape policy, investment decisions and the pace at which sustainable materials reach the market."

Two of the proposed categories can be implemented immediately. Biogenic global warming potential is already included in established methods such as those from the Intergovernmental Panel on Climate Change (IPCC), requiring practitioners to report biogenic and fossil carbon separately rather than as a combined figure. Biodiversity impact can be calculated using an existing land use method already available in common LCA software. The remaining five categories require new data to be collected, though the report recommends early adoption with transparent documentation of data gaps and uncertainty.

The report builds on previous BB-REG-NET research that found when assessing bio-based and fossil-based bottles using existing ISO standards, environmental scores could vary by 103 per cent purely due to methodological choices. That work called for mandatory use of EN 18027:2025, a standard published in April 2025 designed to eliminate bias when comparing fossil and bio-based materials.

The Seven Steps to Fairness framework addresses the challenge of identifying impact categories that enable this. The report states that implicit bias can arise from three sources – how environmental impacts are shared between a product and its co-products, how carbon from biological sources is handled, and which impact categories are included in the assessment.

Sarah Davidson, Technology Development Lead at Croda Europe, a chemical manufacturer specialising in bio-based materials, commented: "Continuing to rely on assessment frameworks that overlook key impacts such as biodegradability, persistence and microplastic formation risks locking in fossil-based solutions by default. Updating LCA methodologies is therefore not only about scientific accuracy, but about removing structural barriers to more sustainable materials."

The report identifies that the proposed new impact categories would require four new datasets: bioavailability by material, biological half-life by material, organism loss rates by species type, and compound persistence by chemical compound. Some data already exists in published literature and could be collated, while other measurements would require new research.

Data requirements

For biodegradability, the framework proposes assessing bioavailability – the extent to which a material is accessible to microbes and environmental conditions that drive degradation – in land, water, and air environments. Biodegradation depends on how long it takes for natural breakdown processes to occur, with bioavailability identified as a major determinant of degradation rates.

The microplastic formation category would assess the potential for materials to generate microplastic particles. The report notes that while biodegradable materials initially fragment into microplastics during breakdown, these particles continue to biodegrade and mineralise, contrasting with conventional plastics that persist in the environment. This aligns with separate BB-REG-NET evidence demonstrating that certified biodegradable materials undergo complete mineralisation rather than accumulating.

The persistence category would assess how long chemical compounds remain in the environment by considering the persistence of compounds within a material and the proportion of each compound present. Bioaccumulation – the potential for substances to build up in organism tissues – would require data on biological half-life and organism loss rates for different species types.

The report recommends that practitioners adopt these additional impact categories at the earliest opportunity, presenting results with appropriate uncertainty parameters and documentation of data gaps. "By including these impact categories in comparative assessment sooner rather than later, the potential influence of these impacts can be considered, even during methodological development and data collection," the report states.

Previous BB-REG-NET research identified that if 30 per cent of chemicals could be bio-based by 2050, the UK bioeconomy could generate £204 billion in annual revenue, with manufacturing of twelve biochemicals alone contributing 5.2 million tonnes of CO₂ equivalent greenhouse gas savings annually.

The report authors will discuss the findings in a webinar on 11 February 2026.