Nippon Steel backs $3 billion upgrade of US Steel's Mon Valley plant
US Steel, owned by Nippon Steel, will spend about $3 billion to expand its Edgar Thomson facility in Pennsylvania, adding a new hot-strip mill and boosting capacity by roughly 60%.
US Steel announced a $3 billion (approximately ¥470 billion) investment in its Edgar Thomson plant at the Mon Valley Works in Pennsylvania, a move approved by the board earlier this month. The upgrade will add a new hot-strip mill, increasing the plant’s annual steel-making capacity by about 60% to roughly 3.5 million tons, with the new line expected to run by 2029. David Burritt, US Steel’s President and CEO, highlighted that the project introduces world-class technology and expands service to markets including automobiles, home appliances, and the energy sector.
Nippon Steel, which completed its acquisition of US Steel in June 2025, expects the expansion to create thousands of jobs and generate up to $1.7 billion in tax and economic benefits within three years. This spending represents the biggest single investment in Nippon Steel’s U.S. strategy, part of a broader $11 billion commitment through 2028.
Why it matters
The upgrade will significantly boost U.S. steel capacity, create jobs and strengthen supply chains for key industries.
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