Several of Westlake's operations which produce petrochemicals and plastics have earned the prestigious ISO 9001:2008 certification or the new ISO 9001:2015 certification. ISO certification signifies that a company has an ongoing program of continual quality improvement. Either ISO 9001:2008 or ISO 9001:2015 certification indicates that Westlake's production facilities meet rigid standards and supplier requirements and are committed to continual improvement.

Westlake Chemical Corporation operations with ISO 9001:2008 or ISO 9001:2015 certification include the following:

(Click on location below to view certificate)


Westlake Longview

Westlake Vinyls, Inc. and/or Westlake Chemical OpCo. LP - Calvert City

Westlake Chemical Op-Co Lake Charles

Westlake Polymers

Westlake Styrene

Westlake Geismar


Quality / ISO Certification

ISO 9001 (Gallman, Madison, & Prairie)

ISO 14001 (Aberdeen, Gallman, Madison, & Prairie)

Beauharnois, QC (English)

Beauharnois, QC (French)

Lake Charles, LA

Natrium, WV

Plaquemine, LA

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