Reusing concrete products in indoor environments: chemical hazard assessment

The reuse of construction products is promoted as a strategy for reducing environmental impacts and consumption in construction. In indoor environments, reuse raises challenges related to hazardous chemical substances and the interpretation of regulatory obligations, for which legislation and practice provide limited guidance. These challenges are particularly pronounced when products originate from older buildings and lack material documentation. This study examines how chemical hazard assessment can be operationalised in the reuse of construction products in indoor environments in the Finnish context. The analysis focuses on concrete products originating from indoor conditions and combines regulatory and literature analysis, expert engagement and empirical analysis of chemical emission data. The results suggest that the relevance of hazardous substances in reuse is context-dependent and linked to exposure conditions, not solely to the presence of substances. Chemical safety can be assessed through a staged approach based on investigation practices, including building use history, demolition audits and targeted assessments, without routine laboratory testing. Empirical evidence from more than 1,300 concrete samples supports this interpretation, showing low emission levels. The findings suggest that chemical hazards do not appear to constitute a barrier to reuse in typical indoor environments but highlight the need for clearer, consistent regulatory interpretation.

POLICY RELEVANCE

This study highlights the need to align chemical, construction and product-related legislation with the practical realities of construction product reuse. Current regulatory frameworks are largely developed for new products and do not provide clear guidance for assessing chemical hazards in reuse contexts. This creates interpretative uncertainty in building permitting process and may lead to unnecessary testing requirements or overly conservative decision-making. The findings suggest that policy development should focus on clarifying how legislation is interpreted and applied in reuse situations. There is also a need to support consistent assessment practices that consider product origin, use history and exposure conditions. Improving the quality of demolition audits and strengthening information transfer across project actors are enabling measures. Although based on the Finnish context, the findings are relevant, as regulatory gaps and uncertainties affect reuse practices in many countries. By promoting proportionate, context-based approaches, policy can support the reuse while maintaining health protections.