This bill creates new law by adding several sections to chapter 19.27 RCW and one section to chapter 43.330 RCW to require embodied carbon emissions accounting and reductions for large buildings. It applies, except for school district construction, to new construction, additions, and renovations of buildings covered by the International Building Code that are 100,000 square feet or larger. The State Building Code Council (SBCC) must adopt rules, consulting the Department of Enterprise Services, Department of Commerce, Department of Ecology, the University of Washington, an existing technical work group, and others, to implement the standards and define covered products and calculation methods. The bill establishes three compliance pathways: a reuse pathway (retain at least 45% of existing structure/envelope and add no more than 50% to total area), a product-level pathway (project-level accounting of A1–A3 life-cycle stage emissions for at least 90% of covered products using product-and-facility-specific Environmental Product Declarations (EPDs)), and a whole-building life-cycle assessment (LCA) pathway comparing embodied carbon to a reference building. Design professionals of record (licensed architects or engineers) must update embodied carbon calculations with procured product and facility-specific EPDs, attest to their accuracy with a stamped letter, and submit required attestations and reports with permit documents. The Department of Commerce must maintain a public database for reported emissions reductions, create a public education website, and randomly audit three percent of projects annually. The SBCC must require productand facility-specific EPDs or whole-building LCA reporting in the 2024 code cycle, use industry-regional EPDs if product/facility-specific EPDs are not available before the 2027 code, and adopt code changes in the 2027 and 2030 cycles that move toward a 30 percent embodied carbon reduction. Projects permitted under the 2030 state building code must achieve a 30 percent reduction in embodied carbon from a project-wide static baseline (using Carbon Leadership Forum 2023 material baselines or comparable data) or a 30 percent reduction compared to the reference building under the whole-building LCA pathway. SBCC must report progress by December 31, 2028, and every three years thereafter; the Department of Commerce reports major database and audit findings on the same schedule. Important implementation details are deferred to SBCC rulemaking and are not specified here. The bill text in these excerpts does not specify the exact definitions or methods for "covered products," how to calculate the 90 percent threshold or the 45 percent reuse, the static baseline methodology for the 30 percent reduction, enforcement mechanisms, penalties, funding, full database schema or public access details. Also, the excerpt shows a possible numbering error in Sec. 5 with two subsections labeled "(2)."

If enacted, large building projects (100,000 square feet and up, excluding school districts) will face new embodied-carbon reduction and reporting obligations that will likely increase upfront design and compliance work and add material documentation costs. Architects and engineers of record will need to perform or update embodied-carbon calculations using productand facility-specific EPDs or whole-building LCAs, stamp and submit attestations with permits, and choose a compliance pathway (reuse, product-level, or whole-building LCA). Developers and builders should expect added costs for LCAs, acquiring EPDs or substituting lower-carbon materials, and possible redesigns to meet a 30% reduction target phased in by the 2030 code; manufacturers will face more demand for product-and-facility-specific EPDs, with industry/regional EPDs allowed only if product-specific ones are unavailable by 2027. State agencies will take on new rulemaking, oversight, and reporting duties: the State Building Code Council must define covered products, calculation methods, and phase-in rules for 2027 and 2030, while the Department of Commerce must maintain a public project database and educational website, conduct random audits of about 3% of projects annually, and publish findings starting December 31, 2028 and every three years thereafter. Important implementation details that affect actual costs and compliance risk—how “covered products,” the 45% reuse calculation, the 90% product coverage metric, the static baseline methodology for the 30% target, and enforcement or penalties—are deferred to later SBCC rules or are unclear in the text, so exact burdens and outcomes remain uncertain.