U.S. Steel’s board approved full funding for a nearly $3 billion Pennsylvania mill, a project expected to raise annual capacity at Mon Valley Works by about 1.3 million tons.
The Edgar Thomson Plant near Pittsburgh is slated to host the mill. U.S. Steel expects annual production capacity at Mon Valley Works to rise from about 2.2 million tons to 3.5 million tons.
Construction depends on required permits, and the company expects initial production in late 2029. A slab-sizing press will be installed within the production line alongside walking-beam furnaces. U.S. Steel says the design should reduce fuel consumption and waste while giving the mill more flexibility to serve automotive, appliance and line pipe markets.
U.S. Steel also cited projections of 5,100 to 6,300 jobs, $46 million to $58 million in state and local tax revenue, and up to $1.7 billion in economic impact over three years.
The project follows earlier plans for a Mon Valley mill. Nippon Steel said in August 2024 it would invest at least $1 billion in Mon Valley Works, including replacing or upgrading its hot strip mill and other facilities. A June 2026 U.S. Steel analysis described a $2 billion to $2.5 billion investment scenario and said the project would replace an 87-year-old mill at the nearby Irvin Plant. That mill was slated for decommissioning, according to the analysis.
Nippon Steel and U.S. Steel finalized their partnership in June 2025. Under a National Security Agreement, Nippon Steel committed about $11 billion in new investments in U.S. Steel by 2028.
A Sept. 30 draft report from the Allegheny County Health Department said modeling showed the project would meet applicable air-quality standards. The report identifies Braddock as an Environmental Justice area and ties emissions offsets to phasing out the Irvin mill as Edgar Thomson ramps up.
WESA reported that residents raised pollution concerns at an Oct. 15 air-permit meeting. WESA quoted Braddock Councilwoman Patricia Kelley as saying, “ [They’re] moving their pollution over here.” Another county meeting is scheduled for Nov. 10, with public comments accepted through Nov. 18, WESA reported.
