United States Steel Corp was incorporated in the State of Delaware. The Company is an integrated steel producer of flat-rolled and tubular products with production operations in North America and Europe. An integrated producer uses iron ore and coke as primary raw materials for steel production. It is also engaged in other business activities consisting of railroad services and real estate operations. The Company has three reportable operating segments: Flat-rolled Products (Flat-rolled), U. S. Steel Europe (USSE) and Tubular Products (Tubular). The Flat-rolled segment includes the operating results of U. S. Steel's North American integrated steel plants and equity investees involved in the production of slabs, rounds, strip mill plates, sheets and tin mill products, as well as all iron ore and coke production facilities in the United States and Canada. These operations serve North American customers in the service center, conversion, transportation (including automotive), construction, container, and appliance and electrical markets. Flat-rolled supplies steel rounds and hot-rolled bands to Tubular. The USSE segment includes the operating results of U. S. Steel Košice (USSK), U. S. Steel's integrated steel plant and coke production facilities in Slovakia. Prior to January 31, 2012, the USSE segment also included the operating results of USSS, U. S. Steel's integrated steel plant and other facilities in Serbia, and an equity investee, which were sold on January 31, 2012. USSE serves customers in the European construction, service center, conversion, container, transportation (including automotive), appliance and electrical, and oil, gas and petrochemical markets. USSE produces and sells slabs, sheet, strip mill plate, tin mill products and spiral welded pipe, as well as heating radiators and refractory ceramic materials. The Tubular segment includes the operating results of U. S. Steel's tubular production facilities, in the United States, and equity investees in the United States and Brazil. These operations produce and sell seamless and electric resistance welded (ERW) steel casing and tubing (commonly known as oil country tubular goods or OCTG), standard and line pipe and mechanical tubing and serve customers in the oil, gas and petrochemical markets. The Company's other businesses include railroad services and real estate operations. The Company owns, develops and manages various real estate assets, which include approximately 200,000 acres of surface rights in Alabama, Illinois, Maryland, Michigan, Minnesota and Pennsylvania. In addition, the company participates in joint ventures that are developing real estate projects in Alabama, Maryland and Illinois. The Company also owns approximately 4,000 acres of land in Ontario, Canada, which could potentially be sold or developed. The Company's businesses in the United States are subject to numerous federal, state and local laws and regulations relating to the protection of the environment. These environmental laws and regulations include the Clean Air Act (CAA) with respect to air emissions; the Clean Water Act (CWA) with respect to water discharges; the Resource Conservation and Recovery Act.