Sasol won’t make the final decision on a multibillion-dollar natural gas-to-liquids facility in Westlake until late 2016 but will announce its decision on an ethane cracker by the end of the year, President and Chief Executive Officer David Constable said during a Monday conference call with stock analysts and investors.

The gas-to-liquids facility will convert natural gas to diesel. The cracker breaks natural gas into smaller molecules to make ethylene, used in making plastics. Both projects are now in the front-end engineering and design, or FEED, stage. The complex’s cost has been estimated at between $16 billion and $21 billion.

Constable listed a handful of important points about the Westlake complex, including Sasol has secured ethane feedstock supply agreements and air, water and wetlands permits for both the cracker and the gas-to-liquids facility Sasol has also made progress on financing the megaproject.