BAKER BOTTS L.L.P.                            ONE SHELL PLAZA         AUSTIN
                                              910 LOUISIANA           BAKU
                                              HOUSTON, TEXAS          DALLAS
                                              77002-4995              HOUSTON
                                              713.229.1234            LONDON
                                              FAX 713.229.1522        MOSCOW
                                                                      NEW YORK
                                                                      RIYADH
                                                                      WASHINGTON

November 21, 2003

Westlake Chemical Corporation
2801 Post Oak Boulevard, Suite 600
Houston, Texas 77056

Ladies and Gentlemen:

                  As set forth in the Registration Statement on Form S-4
(Registration No. 333-108982; the "Registration Statement") filed with the
Securities and Exchange Commission (the "Commission") by Westlake Chemical
Corporation, a Delaware corporation (the "Company"), and the additional
registrants listed on the facing page of the Registration Statement (the
"Guarantors") under the Securities Act of 1933, as amended (the "Act"), relating
to the registration under the Act of the offering and issuance of $380 million
aggregate principal amount of the Company's 8 3/4% Senior Notes due 2011 (the
"New Notes") guaranteed by the Guarantors (the "Guarantees"), to be offered by
the Company and the Guarantors in exchange (the "Exchange Offer") for a like
principal amount of the Company's issued and outstanding 8 3/4% Senior Notes due
2011 guaranteed by the Guarantors (the "Old Notes"), certain legal matters in
connection with the New Notes and the related Guarantees are being passed upon
for you by us. The New Notes and the related Guarantees are to be issued under
an Indenture, dated as of July 31, 2003 (the "Indenture"), among the Company,
the Guarantors and JPMorgan Chase Bank, as trustee (the "Trustee"). At your
request, this opinion is being furnished to you for filing as Exhibit 5.1 to the
Registration Statement.

                  In our capacity as your counsel in the connection referred to
above, we have examined the Company's Certificate of Incorporation and bylaws,
each as amended to date, and the Certificate of Incorporation or Certificate of
Limited Partnership, as applicable, and the bylaws or limited partnership
agreement, each as amended to date, of each of the Guarantors, and originals, or
copies certified or otherwise identified, of the Indenture, corporate or
partnership records of the Company and the Guarantors, including minute books of
the Company and the Guarantors, as furnished to us by the Company and the
Guarantors, certificates of public officials and of representatives of the
Company and the Guarantors, statutes and other instruments and documents as a
basis for the opinions hereinafter expressed. We have assumed that the
signatures on all documents examined by us are genuine, all documents submitted
to us as originals are authentic and all documents submitted to us as certified
or photostatic copies conform to the originals thereof. We also have assumed
that (i) the Indenture has been duly authorized, executed and delivered by the
Trustee and constitutes the legal, valid and binding obligation of the Trustee,
(ii) the Registration Statement will have become effective under the Act and the
Indenture will have been qualified under the Trust Indenture Act of 1939, as
amended, (iii) the Guarantee of Westlake Overseas Corporation, a U.S. Virgin
Islands corporation ("WOC"), endorsed on the New Notes will have been duly
authorized, executed and delivered by WOC and (iv) the New Notes and the related
Guarantees will have been duly executed, authenticated and delivered in
accordance with the provisions of the Indenture and



BAKER BOTTS L.L.P.

                                                               November 21, 2003



issued in exchange for Old Notes pursuant to, and in accordance with the terms
of, the Exchange Offer as contemplated in the Registration Statement.

                  On the basis of the foregoing, and subject to the
qualifications and limitations hereinafter set forth, we are of the opinion
that:

                  1. The New Notes, when issued, will constitute legal, valid
         and binding obligations of the Company, enforceable against the Company
         in accordance with their terms, except as that enforcement is subject
         to (a) any applicable bankruptcy, insolvency, reorganization,
         moratorium, fraudulent transfer or conveyance or other laws relating to
         or affecting creditors' rights generally and (b) general principles of
         equity (regardless of whether that enforceability is considered in a
         proceeding in equity or at law).

                  2. Each Guarantee of a Guarantor, when issued, will constitute
         the legal, valid and binding obligation of such Guarantor, enforceable
         against such Guarantor in accordance with its terms, except as that
         enforcement is subject to (a) any applicable bankruptcy, insolvency,
         reorganization, moratorium, fraudulent transfer or conveyance or other
         laws relating to or affecting creditors' rights generally and (b)
         general principles of equity (regardless of whether that enforceability
         is considered in a proceeding in equity or at law).

                  The opinions set forth above are limited in all respects to
matters of the law of the State of New York, the General Corporation Law of the
State of Delaware, the Revised Uniform Limited Partnership Act of the State of
Delaware and applicable federal law. We hereby consent to the filing of this
opinion of counsel as Exhibit 5.1 to the Registration Statement. We also consent
to the reference to our Firm under the heading "Legal Matters" in the prospectus
forming a part of the Registration Statement. In giving this consent, we do not
hereby admit that we are in the category of persons whose consent is required
under Section 7 of the Act or the rules and regulations of the Commission
thereunder.

                                                     Very truly yours,


                                                     /s/ Baker Botts L.L.P.
                                                     ----------------------

JDK/TRF/JAS

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