At the peak of Carnegie steel it was worth approximately $480 million (the price that Carnegie also later sold his company as), counting the fact that HomeStead Steel Works was also bought and merged into Carnegie Steel. His business headquarters was located at Pittsburgh, Pennsylvania. At the peak they had 15 buildings in total, eight steel mills, two iron mills, two rail mills, two processing miles and one forge. Despite Carnegie being considered a philanthropist, he treated his workers horribly. He made his workers work long hours (12 hours) with barely any holidays or days off.
Despite how long his workers worked in the mills and how rich Carnegie was, the workers got barely enough wages to live off of. Even with how little Carngie's workers were being paid, in 1892 the workers got their pay docked by 30%. This then caused the workers to unionize later on July 6th 1892. Called the homestead strike and/or riot. This was a strike but turned violent when shots were fired and people were killed and injured. Carnegie no longer let his workers unionize after that.