Pittsburgh’s iron furnaces came late. For most of the first half of the 19th century the city was famous for working iron rather than making it. Its forges and rolling mills turned pig iron from furnaces in the countryside into bar, sheet and nails. The blast furnaces that smelted iron ore inside the city came mostly after 1859, when a South Side company proved that a furnace burning Connellsville coke could work. Within a generation those furnaces were feeding steel mills, and the iron age gave way to the steel age. This is that story, told from the records that survive.
A false start in 1792
The first blast furnace in what is now Pittsburgh was George Anschutz’s, and it did not last. The state’s ExplorePAHistory page for the Clinton Furnace marker says Anschutz built a charcoal furnace in 1792 and abandoned it two years later. (Bob Regan, writing in Pittsburgh City Paper, gives 1793, places it in today’s Shadyside, and says it failed after about a year.) After that, the same state page says, Pittsburgh “became a center for secondary ironworks, such as forges and rolling mills, that finished pig iron produced at furnaces outside the city.” Charcoal furnaces needed forests for fuel, and they were scattered across the countryside where the timber was.
From charcoal to coke: Clinton Furnace, 1859
The change came on the South Side. The Pennsylvania Historical and Museum Commission marker at Bessemer Court in Station Square calls Clinton Furnace “Pittsburgh’s first successful blast furnace for making pig iron” and says operations began nearby in 1859 “using Connellsville coke as fuel.” Its builder, according to ExplorePAHistory, was Graff, Bennett and Company, one of the city’s rolling-mill firms, which wanted to make its own iron instead of buying it.
The fuel was the point. The state’s account says Clinton first used coke from the Connellsville section of the Pittsburgh coal seam, then tried cheaper coke from locally mined coal, failed, and went back to Connellsville coke, which “operated more efficiently, and produced better quality iron.” An 1891 account in Popular Science Monthly tells it the other way round, with coke from Pittsburgh coal tried first and Connellsville coke adopted in the spring of 1860. The same page credits the furnace with 11,000 tons of iron a year, which it calls more than twice the output of a typical anthracite furnace and six times the average charcoal furnace, and says the key was a blast pressure of eight pounds per square inch when most furnaces used three to five. The marker says Clinton “initiated a new era” and that operations ended in 1927. The coal behind all this is the subject of our piece on Pittsburgh coal.
Eliza, 1859 to 1860
Jones & Laughlin’s furnaces followed almost at once. A University of Pittsburgh archives description says that in July 1859 Laughlin & Company acquired land on the north side of the Monongahela, opposite what is now the South Side, and built two blast furnaces called the Eliza furnaces along with beehive coke ovens, and that they began operating in 1860. The same description says it was common to name furnaces after wives, daughters and mothers, and that Eliza was chosen because the name was common in both the Jones and Laughlin families. Benjamin F. Jones had bought a share in the American Iron Works in 1851, according to Pitt’s finding aid for the company’s records, and the two men’s partnership dates to 1861.
The sources disagree on the order. Pitt’s description calls the Eliza furnaces “the second blast furnaces built in the Pittsburgh metropolitan area,” while the state’s account calls Clinton “only the second furnace constructed in Pittsburgh,” counting Anschutz’s as the first. Both can be roughly true only if the counts are made differently, and I could not settle it.
Eliza grew into a huge plant. Pitt’s description says the works, also called the Soho or Pittsburgh Works, reached an ingot capacity of two million tons a year in 1930 and employed more than 5,000 people at one time, closed in 1977, and that the furnaces were razed in the mid-1980s. The riverside bike path between Downtown and Oakland, the Eliza Furnace Trail, carries the name. The Greater Hazelwood Community Collaborative places Laughlin’s furnaces on the Hazelwood riverfront; for that neighborhood, see our piece on the Woods House in Hazelwood.
The men at the furnaces
The best evidence for what furnace work was like comes from the Pittsburgh Survey, the investigation of the city’s working life whose findings were published in six volumes. In The Steel Workers (1911), John A. Fitch wrote that the demand for unskilled labor had made Pittsburgh “a veritable Mecca to the immigrant,” and that of the nearly 7,000 men at Homestead, “more than half are Slavs, and two-thirds are foreign born.” He described twelve-hour shifts and a “twenty-four hour shift, which is experienced fortnightly in Allegheny County by nearly 6,000 blast furnace men.” Fitch was describing the steel era, not the 1860s, and I did not find comparable figures for the early coke furnaces.
From pig iron to steel
The blast furnace did not disappear when steel arrived. The steel companies wanted their own supply of iron, and the Carrie Furnaces, below, were bought for exactly that reason: to feed Homestead’s open-hearth steel furnaces. Anne Madarasz of the Heinz History Center told The Pitt News that the shift began after Andrew Carnegie returned from Europe in 1872 having learned the Bessemer process. For what followed, see how the steel industry shaped Pittsburgh and our profile of Carnegie.
Carrie Furnaces
The surviving monument to Pittsburgh ironmaking is across the river from Homestead. A 2002 draft environmental assessment for the Carrie Furnaces and the Homestead battle site, posted by the website NPS History, says Carnegie bought the Carrie Furnace Company’s ironworks, which then had two blast furnaces, in 1898, to supply iron for the open-hearth furnaces at the Homestead Works. In 1900 and 1901, the same report says, Carnegie Steel built the Hot Metal Bridge to carry molten iron across the Monongahela to Homestead, creating a fully integrated plant. That is the Homestead of the 1892 strike.
The two furnaces that still stand, Numbers 6 and 7, were built in 1906 and 1907 to expand the plant, according to that report, and the National Park Service’s updated landmark documentation says construction began in 1906 and was finished the following year. They were designated a National Historic Landmark in 2006. Rivers of Steel, which runs tours there, says they stand 92 feet tall and are the only non-operating blast furnaces left in the region. Dates for the earlier plant vary. A frequently repeated figure says the site operated from 1884 to 1982, and one online summary gives 1881 as the year the first Carrie furnace was built, while also dating the shutdown of Numbers 6 and 7 to 1978. I could not confirm the founding year from a primary source.
What remains
Very little of Pittsburgh’s iron age survives above ground. The Clinton Furnace marker stands along the riverwalk at Station Square. The Eliza furnaces are gone, though the name lives on in the trail. Carrie Furnaces 6 and 7, open for tours, are the best place to stand next to a blast furnace and see how big the business became. For the towns those furnaces fed, see the Steel Valley story.
