Embodied carbon policies represent a paradigm shift in industrial decarbonization, yet their effectiveness hinges critically on the quality and transparency of the Environmental Product Declarations (EPDs) used to verify embodied carbon. This study addresses this knowledge gap through a comprehensive analysis of EPD utility for strategic policymaking.We systematically evaluated 207 EPDs with 500 individual product records across six material categories relevant to California's construction sector. Our analysis assessed EPD reporting frequency for critical parameters including production technologies, supply chain characteristics, fuel and electricity mixes, recycled content, and data quality metrics essential for confident embodied carbon threshold setting and reduction pace determination.Findings reveal that most EPDs lack specificity on production technologies, supply chain locations, direct fuel usage, and electricity procurement details. Data quality reporting beyond minimum requirements remains rare, hampering policymakers' ability to assess declaration reliability and establish performance frontiers. We provide evidence-based recommendations for enhancing EPD standards.