Westlake Chemical Corporation is a manufacturer and marketer of basic chemicals, vinyls, polymers and building products. The Company operates through two segments: Vinyls and Olefins. The Vinyl segment manufactures and markets polyvinyl chloride (PVC), Vinyl Chloride Monomer (VCM), ethylene dichloride (EDC), chlor-alkali (chlorine and caustic soda), chlorinated derivative products and ethylene. The Company also manufactures and sells building products fabricated primarily from PVC, including residential siding, trim and moldings, pipe and fittings for various water, sewer and industrial applications, profiles for windows and doors. The Olefins segment manufactures and markets polyethylene, styrene monomer and various ethylene co-products. The Company's ethylene production is used in the Company's polyethylene, styrene and VCM operations. In addition, the Company also sells ethylene and ethylene co-products, primarily propylene, crude butadiene, pyrolysis gasoline and hydrogen.