U.S. Steel Edgar Thomson Plant
Large load · 1300 BRADDOCK AVENUE, Braddock, PA
The Edgar Thomson plant in Braddock, Pennsylvania, founded by Andrew Carnegie in 1875, is the steelmaking heart of U.S. Steel's Mon Valley Works. It is the last integrated steel producer in Pennsylvania with blast furnaces and basic oxygen furnaces. It makes slabs today and ships them by rail to the Irvin Works for hot rolling. Under Nippon Steel ownership, U.S. Steel is building a new hot strip mill at Edgar Thomson, part of up to $2.5 billion in Mon Valley investment, with production expected in the second half of 2029. That mill would move rolling load from Irvin to Braddock. No source gives the plant's grid demand or its electric supply arrangements.
Overview
U.S. Steel said in June 2026 it would invest up to $2.5 billion in Mon Valley Works, including a new hot strip mill at Edgar Thomson that replaces the 87-year-old mill at Irvin. It is evaluating $2 billion and $2.5 billion scenarios, and the package includes a new ladle metallurgy furnace and a slag recycler, which is already under construction. Construction of the mill was set to begin later in 2026, with production expected in the second half of 2029. The company says the investment will cut energy use as well as improve yields and quality.
Profile
- Energy changes in the process
- Today slabs cast at Edgar Thomson travel about seven miles by rail to Irvin, where they are reheated before rolling. A company director told a July 2026 open house that Irvin has five reheat furnaces and the new mill will have two, with much higher efficiency. Rolling at the steelmaking site removes that second reheat. Irvin will keep finishing steel, mainly for appliances.
- Ownership and the Nippon pledge
- Nippon Steel completed its purchase of U.S. Steel in 2025, after agreeing in 2024 to spend at least $1 billion on a hot strip mill in southwestern Pennsylvania. The scope later grew to the Mon Valley program. U.S. Steel's Pittsburgh-area plants employ about 3,000 union steelworkers, and the company said it would file permit applications with Allegheny County for the new mill.
Facility
- Activity
- Integrated ironmaking and steelmaking (blast furnace and basic oxygen furnaces) producing steel slabs; new hot strip mill planned
- Industry
- Manufacturing
- Site type
- Facility
- Operating status
- Operating
Related records
Timeline
- Jun 8, 2026
- U.S. Steel announces up to $2.5 billion Mon Valley investment including a new hot strip mill at Edgar Thomson
US Steel doubles investment to more than $2B for oldest plant | Manufacturing Dive
- Jul 1, 2029
- New hot strip mill expected to begin production in the second half of 2029
US Steel doubles investment to more than $2B for oldest plant | Manufacturing Dive