The new unit, with a pricetag over half a billion dollars, adds 450,000 metric tons of polypropylene production, doubling the Baton Rouge Polyolefins plant's capacity, Exxon said.

The new unit employs 65 full-time staff, the company said. More than 650 people were employed during construction.

Polypropylene is used in making a wide variety of products from food and drink containers, plumbing, disposable diapers and in medicine.

(Reporting by Erwin Seba, Editing by Louise Heavens)