This study examines the construction, dynamics and appropriation of Environmental Performance Indicators (EPIs) within an organization, specifically focusing on their development process. Over the course of a year, the author conducted more than 50 interviews and 30 meetings with stakeholders to analyze the development of EPIs in new product development. The research highlights the roles of experts, project teams, and executive management in EPI construction, emphasizing stakeholder learning and compromises. The findings enrich the discussion on stakeholder integration in EPI processes and the roles of eco-design tools, particularly during preliminary development stages, addressing the gap between academic research and practical application.