EXHIBIT 3.4

                            CERTIFICATE OF AMENDMENT
                       TO THE CERTIFICATE OF INCORPORATION
                                       OF
                          WESTLAKE CHEMICAL CORPORATION

                  Pursuant to the provisions of Section 242 of the Delaware
General Corporation law, and as duly authorized this date by consent of the
shareholders of Westlake Chemical Corporation ("the Corporation"), the
Corporation adopts this certificate of Amendment to its Certificate of
Incorporation, such that ARTICLE IV thereof shall read as follows:

                                   "ARTICLE IV

                  The total number of shares which the Corporation has the
         authority to issue is ten thousand (10,000) shares of common stock at a
         par value of One and No/100 Dollars ($1.00) each ("Common Stock"), and
         1000 shares of Preferred Stock, without par value.

                  The Corporation may issue one or more series of Preferred
         Stock. The Board of Directors is hereby vested with authority from time
         to time to establish and designate such series, and to fix and
         determine the relative rights and preferences of the shares of any
         series, and to increase or decrease the number of shares within each
         series; provided that the Board of Directors may not decrease the
         number of shares within a series below the number of shares within such
         series that is then issued and outstanding. The voting powers,
         designations, preferences, rights and qualifications, limitations or
         restrictions of any series of Preferred Stock may be set forth in a
         certificate of designations provided for in a resolution or resolutions
         adopted by the Board of Directors."

                  The number of shares of common stock in the Corporation
authorized at the time of such adoption was 1,000 shares $1.00 par value per
share ("Common Stock") and 1,000 shares of no par value Preferred Stock,
("Preferred Stock") of which 1,000 shares of Common Stock, and 890 shares of
Preferred Stock are issued and outstanding and entitled to vote at the meeting.
The number of shares of Common Stock voted for such amendment was 1,000; the
number of shares of Preferred Stock voted for such amendment was 890 and there
were no shares voted against such amendment.

                  THUS DULY AUTHORIZED AND ADOPTED effective this 12th day of
August, 1997.

ATTEST:                                              WESTLAKE VINYL CORPORATION

/s/ Louis B. Trenchard III                           By: /s/ A. Chao
---------------------------                             ------------------------
Louis B. Trenchard III                                   Albert Chao, President
Assistant Secretary