Cheniere Energy is boosting its investment in its Sabine Pass liquefied natural gas export facility in Cameron Parish by $6 billion to build two production units in addition to the four already under construction.

The two units lift the total project cost to $18 billion, the company said. About 120 new direct jobs will be created on top of the 280 already expected from the first four production units, with pay averaging $100,000 per year, plus benefits.

The first of those units are expected to begin production in 2015. The final two units will begin production in 2019.

An estimated 4,500 construction jobs are projected at the peak of building activity.

Four years ago, Cheniere Energy announced the development of a natural gas liquefaction facility and export terminal to be built adjacent to Cheniere’s existing LNG import receiving terminal in Cameron Parish.

Construction began in August 2012. Nearly all the LNG production capacity for the first five liquefaction units has been sold under 20-year contracts with major global clients.

Hiring for the positions created by the initial announcement began in 2013, and hiring for the newly created positions will begin in 2015.