The chemicals business of Occidental Petroleum, Occidental Chemical (OxyChem) manufactures basic chemicals, vinyls, and performance chemicals. The chemical production company is the top US maker of chlorine and caustic soda (used in bleach, plastics, and pulp and paper) and the top producer of potassium hydroxide, or caustic potash (used in fertilizers). Through subsidiary OxyVinyls it's the leading North American maker of vinyl chloride monomer (VCM), which is used to make polyvinyl chloride (PVC) resins. The company operates some 24 manufacturing plants.