Increasing transparency and traceability of supply chain emissions is critical to accelerate decarbonization in the materials sector. RMI’s Horizon Zero project is advancing this work through the development of sector-specific carbon accounting methodologies. The joint pilot of RMI’s Steel Emissions Reporting Guidance using SINAI Technologies’ dedicated software platform provides a real-world application of RMI’s guidance for the steel sector. It also demonstrates that the collection of process-level primary emissions data makes it easier for companies to respond to increasingly stringent emissions reporting requirements and helps steel producers differentiate their products based on emissions performance. With product-level emissions information, buyers can be confident that their procurement practices are contributing towards industry-wide decarbonization.