Because of its location west of the Allegheny Mountains, excellent river transportation, and high quality bituminous coal deposits, Pittsburgh in the 19th century became one of the nation's most industrialized cities. It was best known for its steel production, but it also produced many other products. Manufactures included aluminum (from the Aluminum Company of America, now ALCOA); electrical generators and appliances (Westinghouse Electric); glass (Pittsburgh Plate Glass, now PPG Industries); coke-making machinery (Koppers); railroad cars and locomotives (Pressed Steel Car Company and Pittsburgh Locomotive); coke and coal chemicals (H. C. Frick & Company and Pittsburgh Coal Company); and food products (H. J. Heinz). Extensive coal mining was also carried on in the Pittsburgh area as well as the processing of coke, essential to the steelmaking process, from soft coal.
By the mid-1980s, however, many of the region's manufacturing plants had gone out of business or left the area. The greatest losses were in steel, with the elimination of over 100,000 steel and steel-related jobs between 1978 and 1983. By the mid-1990s what once was the world's greatest steelmaking complex had been reduced to only one major integrated mill (the Edgar Thompson Works); a specialty steel plant (Allegheny Ludlum); a strip mill (the Irwin Works); and two plants where coke was produced as a by-product. A dramatic sight is the empty land lining the river banks in the Monongahela Valley where steel mills formerly stood. Numerous projects, however, are planned for these sites. For example, the Pittsburgh Technology Park was built on a former industrial site on the north side of the Monongahela River.
