Westlake Chemical Encounters Unscheduled Shutdown of Petro II Ethylene Unit in Lake Charles

HOUSTON, Sept. 11 /PRNewswire-FirstCall/ -- Westlake Chemical Corporation (NYSE: WLK) announced today that it has encountered mechanical problems with a compressor and related equipment at its Petro II ethylene unit in Lake Charles, Louisiana, resulting in an unscheduled shutdown of that unit.

The company currently expects that the shutdown could continue until early October 2006. The company currently estimates further that the negative effect on operating income of the shutdown could be in the range of $20 to $25 million from lost production and maintenance repair costs.

While the Petro II unit is down, the company expects to substantially complete a turnaround of the unit that was scheduled for late this year or early next year. The company also plans during the unit's down time to complete portions of its previously announced Feed-Flex project which will reduce energy costs and provide for additional ethylene capacity. The capitalized cost of the turnaround work is estimated to be $20 million.

The date and the dollar amounts mentioned above are subject to revision as additional analysis and the repairs and other work are performed.

The statements in this release relating to the shut-down and the estimated start-up date and estimated financial effect, as well as any other matters that are not historical facts, are forward-looking statements that are subject to risks and uncertainties. Actual results could differ materially. For more detailed information about factors that could cause actual results to differ materially, please refer to Westlake's Annual Report on Form 10-K for the year ended December 31, 2005, which was filed in February 2006.

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 .

Westlake Chemical Corporation

David R. Hansen, Media Relations
Steven Bender, Investor Relations
both of Westlake Chemical Corporation, +1-713-960-911

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