Westlake Chemical Corporation plans to increase capacity of the previously announced chlor-alkali plant to be located at its vinyls manufacturing complex in Geismar , Louisiana. The chlor-alkali unit originally estimated to produce 250,000 electrochemical units (ECU's) annually will now be designed for a capacity of up to 350,000 ECU's annually. This new plant is consistent with Westlake 's vertical integration strategy for its vinyls business and will allow the company to expand and optimize the vinyls chain over time. The construction costs for this chlor-alkali facility are estimated to range between US$370-420 million . Site work is currently underway for this new facility and the project is targeted for start-up in H2-2013. The project will be partially funded by the Gulf Opportunity Zone bonds issued by the company. The plant will utilize state of the art membrane technology. The new unit will be adjacent to the existing vinyl chloride monomer (VCM) and polyvinyl chloride (PVC) facilities at the Geismar complex.