Discover the cultural and industrial heritage of Southwestern Pennsylvania
Nominate new places or
revise information. Click Here!

U.S. Steel Edgar Thomson Works

Three Rivers

U.S. Steel Edgar Thomson Works


Location Details

PHONE: 412-273-7000
ADDRESS: 13th Street and Braddock Ave
Braddock, PA 15104


It was in Europe during 1872 that Andrew Carnegie saw for himself how easily and cheaply the new Bessemer steel-making process could produce rails. Upon his return to Pittsburgh, he secured an option on 107 acres of farmland along the Monongahela River in Braddock.

Named for the president of the Pennsylvania Railroad and Carnegie’s inaugural customer for steel rail, the Edgar Thomson Works was completed in 1875. ET, as folks in the region call it, was the first large Bessemer plant in the area. (The Bessemer process, which produced steel by forcing a blast of air through molten iron to remove impurities, was introduced in the 1870s in the United States.) Edgar Thomson Works was also Carnegie’s first steel mill and the first of his “integrated” or “basic” steelmaking plants in which the full steelmaking process was completed on site and under one management.

Today, ET, no longer a Bessemer plant, is the lone basic steelmaking mill left in Pennsylvania. While its roots go back to the beginnings of the American steel industry, the plant is among the most modern and productive in the world. As other mills were closing in the 1980s, the Edgar Thomson Works was given a new lease on life with the installation of a $250 million continuous caster. Designed to convert liquid steel directly into slabs, the continuous caster eliminated several costly and time-consuming intermediate steps in the process.

During the 1950s, its peak years of production, Edgar Thomson employed 5,000. Today, ET employs approximately 900 and produces a 500,000-pound heat of high-quality steel every 40 minutes — that’s enough to make nearly 3,000 refrigerators or 5,000 washing machines. Each year, the plant’s 2.8 million tons of raw steel account for 23 percent of the nation’s steel production.

Rivers of Steel enewsletter sign up

Rivers of Steel enewsletter sign up