EXHIBIT 21
SUBSIDIARIES OF WESTLAKE *
| Name of Subsidiary | State or Other Jurisdiction of Incorporation or Organization | Names Doing Business | ||
| North American Pipe Corporation | Delaware | North American Pipe Corporation and NAPCO | ||
| North American Specialty Products LLC | Delaware | North American Specialty Products LLC | ||
| Vinnolit Benelux-France B.V.B.A. | Dendermonde, Belgium | Vinnolit Benelux-France B.V.B.A. | ||
| Vinnolit GmbH & Co. KG | Ismaning, Germany | Vinnolit GmbH & Co. KG | ||
| Vinnolit Hillhouse Ltd. | Lancashire, England | Vinnolit Hillhouse Ltd. | ||
| Vinnolit Italia S.r.L. | Milan, Italy | Vinnolit Italia S.r.L. | ||
| Vinnolit Ltd. | United Kingdom | Vinnolit Ltd. | ||
| Vinnolit Schkopau GmbH | Ismaning, Germany | Vinnolit Schkopau GmbH | ||
| Westech Building Products, Inc. | Delaware | Westech Building Products, Inc. | ||
| Westech Building Products ULC | Canada | Westech Building Products ULC and Westech Building Products Limited | ||
| Westlake Chemical Finance Corporation | Delaware | Westlake Chemical Finance Corporation | ||
| Westlake Chemical OpCo LP | Delaware | Westlake Chemical OpCo LP | ||
| Westlake Chemical Partners LP | Delaware | Westlake Chemical Partners LP | ||
| Westlake Germany GmbH & Co. KG | Ismaning, Germany | Westlake Germany GmbH & Co. KG | ||
| Westlake Longview Corporation | Delaware | Westlake Longview Corporation | ||
| Westlake Management Services, Inc. | Delaware | Westlake Management Services, Inc. | ||
| Westlake Petrochemicals LLC | Delaware | Westlake Petrochemicals LLC, Westlake Petrochemicals LP and WPE | ||
| Westlake Polymers LLC | Delaware | Westlake Polymers LLC, Westlake Polymers LP and WPE | ||
| Westlake PVC Corporation | Delaware | Westlake PVC Corporation | ||
| Westlake Styrene LLC | Delaware | Westlake Styrene LLC and Westlake Styrene LP | ||
| Westlake Supply and Trading Company | Delaware | Westlake Supply and Trading Company | ||
| Westlake Vinyls Company LP | Delaware | Westlake Vinyls Company LP | ||
| Westlake Vinyls, Inc. | Delaware | Westlake Vinyls, Inc., Westlake Monomers and WCAO | ||
| WPT LLC | Delaware | WPT LLC and WPT LP | ||
| Suzhou Huasu Plastics Co., Ltd. | People’s Republic of China | Suzhou Huasu Plastics Co., Ltd. and Huasu | ||
______________________________
| * | Westlake has elected to omit the names of certain subsidiaries. None of the omitted subsidiaries, considered either alone or together with the other omitted subsidiaries of its immediate parent, constitutes a “Significant Subsidiary” as set forth in Section 601(b)(21) of Regulation S-K. |