The antebellum iron industry in Pittsburgh had thrived, fueled by access to coal, iron ore, and other raw materials, as well as transportation routes to get the iron to markets. In 1859, the Clinton and Soho iron furnaces introduced coke-fired smelting to the region. Within three years, the growing needs of the military effort during the Civil War had boosted the city's economy with increased production of iron and armaments, especially at the Allegheny Arsenal and the Fort Pitt Foundry. Arms manufacture included ironclad warships and the world's first 21" heavy artillery gun. By war's end, over one-half of the steel and more than one-third of all U.S. glass was produced in Pittsburgh.