Houston-based Shintech Inc. has filed for an air permit that would allow it to build a 500,000-tons-per-year ethylene plant in Louisiana. Via Plastics News, Shintech is evaluating sites in Plaquemine and Addis, La., where it already has facilities, and Alvin, Texas. The company last June said it would spend $500 million to expand PVC, vinyl chloride monomer and caustic soda capacity by 20-25%. A final investment decision is expected later this year.