The project to make and roll the steel for the World Trade Center began in 1967. Lukens was chosen to produce the steel for the bases of Towers 1 and 2 because of its expertise in small-batch specialty steels able to support incredible loads. Scrap arrived at the plant by truck and train, where it was selected and sorted according to recipes developed to give the steel the needed strength and flexibility. The scrap was melted in an electric arc furnace and poured into molds to form ingots, which were then reheated and rolled to the proper thickness at the rolling mill. The steel plates then went to Plant 5, where they were flame cut into the distinctive tree shape, after which the finished trees were shipped to Pittsburgh-Des Moines for final assembly. The trees were made, rolled, and welded in 1968 and 69 and shipped by rail to New York. Weighing up to 70 tons, they spanned the first nine floors of the World Trade Center towers, which were completed in 1971 at 1,350 feet and 110 stories tall and stood until the tragic day in September, 2001.
