EXHIBIT 3.40

                            CERTIFICATE OF AMENDMENT
                                       OF
                          CERTIFICATE OF INCORPORATION

         Westlake International Corporation ("Corporation"), a corporation
organized and existing under and by virtue of the General Corporation Law of the
State of Delaware, does hereby certify:

         FIRST: That in lieu of a meeting and vote of directors, the Board of
Directors of the Corporation, by unanimous written consent filed with the
Corporation, in accordance with the provisions of Section 141(f) of the General
Corporation Law of the State of Delaware, have adopted a resolution proposing
and declaring advisable the following amendments to the Certificate of
Incorporation of the Corporation:

         RESOLVED, That the Certificate of Incorporation be amended by changing
Article I to read as follows:

                                    ARTICLE I

         The name of the corporation is Westlake Olefins Corporation.

         SECOND: That in lieu of a meeting and vote of stockholders, the holders
of all outstanding stock entitled to vote thereon have given their written
consent to the above amendment in accordance with Section 228 of the General
Corporation Law of the State of Delaware, and said written consent has been
filed with the Corporation.

         THIRD: That said amendments were duly adopted in accordance with the
provisions of Sections 141, 216, 228 and 242 of the General Corporation Law of
the State of Delaware.

         FOURTH: That the capital of the Corporation will not be reduced under
or by reason of said amendments.

         IN WITNESS WHEREOF, Westlake International Corporation has caused this
certificate to be signed by Michael A. Robison, its Vice President, and attested
by Michael A. Robison, its Secretary, this 17th day of July, 1992.

                                             Westlake International Corporation

                                             By:  /s/Michael A. Robison
                                             ------------------------------
                                                  Michael A. Robison
                                                  Vice President

ATTEST:

By:      /s/Michael A. Robison
    -----------------------------------
         Michael A. Robison
         Secretary