An Environmental Product Declaration is a standardised, verified document that communicates the environmental performance of a product based on Life Cycle Assessment results. EPDs provide quantified environmental data using predetermined parameters, enabling comparison between products that fulfil the same function. These declarations are typically prepared according to ISO 14025 and follow specific Product Category Rules (PCRs).
The stated purpose of EPDs is to inform customers and stakeholders about environmental impacts, enabling more environmentally conscious purchasing decisions. However, there is a fundamental methodological contradiction in current EPD practice. Whilst EPDs are explicitly intended to support decision-making between alternative products, all existing EPD schemes require attributional LCA approaches rather than consequential approaches. According to ISO 14040:2006, attributional modelling "assigns elementary flows and potential environmental impacts to a specific product system typically as an account of the history of the product", which does not reflect the physical causalities or actual environmental consequences of choosing one product over another.
The consequential approach, by contrast, "studies the environmental consequences of possible (future) changes between alternative product systems" and provides environmentally relevant information by modelling what actually changes in the world as a result of the decision. This misalignment creates risks: customers using attributional EPDs may inadvertently select options that lead to worse environmental outcomes, as declared values do not represent true environmental consequences.
Best practice involves preparing both consequential and attributional LCAs. The consequential LCA provides environmentally relevant information for actual decision-making, whilst the attributional LCA satisfies current EPD scheme requirements for compliance purposes.
