Occidental Petroleum Corporation engages in the exploration and production of oil and gas properties in the United States and internationally. The company operates in three segments: Oil and Gas; Chemical; and Midstream, Marketing, and Other. The Oil and Gas segment explores for, develops, produces, and markets oil and condensate, natural gas liquids (NGLs), and natural gas. Its domestic oil and gas operations are located in California, Colorado, Kansas, Montana, New Mexico, North Dakota, Oklahoma, Texas, Utah, and West Virginia; and international oil and gas operations are located in Bahrain, Bolivia, Colombia, Iraq, Libya, Oman, Qatar, the United Arab Emirates, and Yemen. As of December 31, 2011, this segment had proved reserves of approximately 3,176 million barrels of oil equivalent. The Chemical segment manufactures and markets basic chemicals, including chlorine, caustic soda, chlorinated organics, potassium chemicals, chlorinated isocyanurates, sodium silicates, calcium chloride, and ethylene dichloride products; vinyls comprising vinyl chloride monomer and polyvinyl chloride; and other chemicals, such as resorcinol. The Midstream, Marketing, and Other segment gathers, treats, processes, transports, stores, purchases, and markets oil, condensate, NGLs, natural gas, and carbon dioxide. This segment also trades around its assets consisting of pipelines and storage capacity, as well as oil and gas, and other commodities; and engages in the power generation activities. The company was founded in 1920 and is headquartered in Los Angeles, California.