Energy and chemical giant Sasol reported Monday it is making progress on the engineering and design of its Westlake complex, a multibillion-dollar project that includes an ethane cracker and a facility to turn natural gas into diesel in southwest Louisiana.

The Johannesburg, South Africa, company expects to reach a final decision on whether to proceed with the ethane cracker sometime this year, and the gas-to-liquids facility 18 to 24 months afterward. The complex’s cost has been estimated at $16 billion to $21 billion.

The ethane cracker breaks natural gas into smaller molecules to make ethylene, which is used in making plastic.

Sasol’s GTL complex is expected to produce more than 96,000 barrels of diesel fuels and chemicals each day. The facilities are expected to create more than 1,250 direct jobs with an average annual salary of nearly $88,000, plus benefits.

Editor’s note: This story was changed March 12, 2014, to correctly identify Sasol as a Johannesburg, South Africa, company.