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U. S. Steel and CarbonFree Sign Definitive Agreement to Capture Carbon Dioxide Emissions at One of the Largest North American Integrated Steel Mills

  • The agreement sets in motion a project to capture emissions from U. S. Steel’s blast furnaces

  • CarbonFree’s SkyCycle™ technology will capture and mineralize up to 50,000 metric tons of carbon dioxide annually at U. S. Steel’s facility in Gary, Indiana, to convert emissions into specialty-grade, carbon-neutral calcium carbonate 

  • The project will be the first commercial-scale carbon capture utilization plant at a steel plant in North America

Pittsburgh, PA & San Antonio, TX — April 3, 2024  United States Steel Corporation (U. S. Steel) (NYSE: X) and CarbonFree, a leader in carbon capture technology, today announced the signing of a definitive agreement to capture carbon emissions generated from U. S. Steel’s Gary Works Blast Furnaces in a first-of-its-kind project. The project will use CarbonFree’s SkyCycle™ technology to capture and mineralize up to 50,000 metric tons of carbon dioxide per year, equivalent to emissions produced by nearly 12,000 passenger cars annually, and will have the opportunity to be expanded in the years to come.

U. S. Steel’s involvement aligns with its goal of reducing greenhouse gas emissions intensity 20% by 2030 and achieving net-zero emissions by 2050. In addition, the initial SkyCycle project responds to the increasing demand for low emissions products, such as verdeX™ advanced sustainable steel, from customers. The project is the first step in exploring the scalability of this technology for potential future implementation across the enterprise. 

Construction on the SkyCycle plant in the U. S. Steel Gary Works facility is expected to commence as early as summer 2024 with operations projected to begin in 2026. The definitive agreement has a term of 20 years following its in-service date. 

CarbonFree’s patented SkyCycle solution captures carbon emissions from hard-to-abate industrial sources before they enter the atmosphere and converts them into a carbon-neutral version of calcium carbonate, which is essential to the creation of paper and plastics, as well as personal care, paint, and building products. CarbonFree-produced calcium carbonate made from captured carbon dioxide can help decarbonize global supply chains by enabling manufacturers to reduce Scope 3 emissions, or it can be stored in an environmentally conscious way without the need for pipelines or disposal wells.

“U. S. Steel is setting a precedent for how manufacturers can and must proactively manage their carbon emissions, and CarbonFree is honored to play a role in this legacy,” said Martin Keighley, CEO of CarbonFree. “At CarbonFree, we are pioneering profitable carbon capture utilization through disruptive specialty chemical manufacturing using waste carbon dioxide as a primary feedstock. As carbon capture continues to be recognized as an indispensable solution on the path to carbon neutrality for carbon-intensive industries, we look forward to helping U. S. Steel achieve its decarbonization goals while providing economic and environmental benefits to the city of Gary and state of Indiana.”

By leveraging cutting-edge carbon capture technologies, U. S. Steel and CarbonFree aim to revolutionize the steel manufacturing industry, reducing carbon emissions and environmental impact. The partnership will likely enable U. S. Steel to offer steel used in the automotive, appliance, and packaging industries with a significantly reduced carbon footprint. 

In addition to capturing carbon dioxide, CarbonFree will use slag produced by the blast furnace operation as part of the calcium carbonate production process.

“Innovating to capture carbon at an integrated mill is the latest example of how steel is enabling a more sustainable future,” said Scott Buckiso, Senior Vice President & Chief Manufacturing Officer, U. S. Steel. “Moreover, U. S. Steel has a history of ‘firsts’ that we’re confidently building on. Using SkyCycle technology for the first project of its kind in North America should benefit the community for generations to come.”

U. S. Steel employs more than 4,300 people at Gary Works. The plant creates an Economic Multiplier Effect, supporting thousands of additional steel plant, chemical, energy, transportation and supplier jobs throughout Lake and Porter Counties and the greater United States.

For more information on SkyCycle, visit the CarbonFree website or follow on LinkedIn

For more information on U. S. Steel, please visit


About U. S. Steel

Founded in 1901, United States Steel Corporation is a leading steel producer. With an unwavering focus on safety, U. S. Steel’s customer-centric Best for All® strategy is advancing a more secure, sustainable future for U. S. Steel and its stakeholders. With a renewed emphasis on innovation, U. S. Steel serves the automotive, construction, appliance, energy, containers, and packaging industries with high value-added steel products such as U. S. Steel’s proprietary XG3® advanced high-strength steel. U. S. Steel also maintains competitively advantaged iron ore production and has an annual raw steelmaking capability of 22.4 million net tons. U. S. Steel is headquartered in Pittsburgh, Pennsylvania, with world-class operations across the United States and in Central Europe. For more information, please visit

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About CarbonFree

CarbonFree is a carbon capture company committed to the decarbonization of hard-to-abate industries and global supply chains. Its SkyCycle technology captures carbon dioxide produced from industrial plants before entering the atmosphere then converts the emissions into chemicals that are pivotal to the specialty chemicals market. CarbonFree’s first-generation technology, SkyMine, has been operational since 2016 and is one of the world’s first and largest industrial-scale carbon mineralization facilities, operating alongside a cement factory in San Antonio. CarbonFree is a member of Carbon Capture Coalition (CCC), Decarb Connect, and American Iron and Steel Institute (AISI) and was part of the first Carbon to Value (C2V) cohort. For more information about CarbonFree, visit