Westlake Chemical Announces Pricing of Secondary Stock Offering for Controlling Stockholder

HOUSTON, April 27, 2006 /PRNewswire-FirstCall via COMTEX News Network/ -- Westlake Chemical Corporation (NYSE: WLK) announced today the pricing of a secondary stock offering of 5.5 million shares of Westlake's common stock for its controlling stockholder, TTWF LP. The shares were priced at yesterday's closing price, and the transaction is expected to close on May 2, 2006, subject to customary closing conditions. Westlake will not receive any proceeds from the offering.

The underwriters for the offering include JP Morgan, Credit Suisse, and Deutsche Bank Securities. TTWF has granted the underwriters an option to purchase up to an additional 825,000 shares to cover over-allotments, if any. A prospectus relating to these securities may be obtained from JPMorgan Securities Inc., Prospectus Department, One Chase Manhattan Plaza, Floor 5B, New York, NY 10081, (212) 552-6164 or addressingservices@jpmchase.com . These documents are being filed with the Securities and Exchange Commission and will be available over the Internet at the SEC's Web site at http://www.sec.gov .

A registration statement relating to these securities has been filed with the Securities and Exchange Commission and is effective. This announcement shall not constitute an offer to sell or the solicitation of an offer to buy nor shall there be any offer of these securities in any jurisdiction in which such offer, solicitation or sale would be unlawful prior to the registration or qualification under the securities laws of any such jurisdiction.

Westlake Chemical Corporation is a manufacturer and supplier of petrochemicals, polymers and fabricated products with headquarters in Houston, Texas. The company's range of products includes: ethylene, polyethylene, styrene, propylene, caustic, VCM, PVC and PVC pipe, windows and fence. For more information, visit the company's Web site at http://www.westlakechemical.com .

Statements in this press release contain "forward-looking" information within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934. These statements involve a number of risks and uncertainties, including conditions in the financial markets and customary closing conditions. Please see the Company's filings with the Securities and Exchange Commission, including without limitation the Company's Annual Report on Form 10-K for the year ended December 31, 2005, filed in February 2006, for a discussion of other factors that may affect forward- looking information.

Westlake Chemical Corporation

David R. Hansen, Media Relations
or Steven Bender, Investor Relations
both of Westlake Chemical Corporation, +1-713-960-9111