US Steel News cover depicting an LST (Landing Ship, Tank)

Pittsburgh’s steel industry proved crucial during World War II. By 1942, U. S. Steel and its subsidiaries smashed 1,000 previous production records. American Bridge Company made nearly 50 LSTs (landing ships, tank). U. S. Steel engineers converted sheet mills, made to produce thin auto steel, into plate mills that ran nearly nonstop, making heavy steel plate for ships and tanks. The region’s mills eventually poured 95 million tons of steel into the war effort. By 1945, Pennsylvania produced as much steel as all the Axis powers combined.