HAWESVILLE, Ky. (AP) — An aluminum producer has begun the return to full production at its smelter in Kentucky, which is planned to open up hundreds of new jobs.

Century Aluminum said in a news release the ceremony Wednesday at Hawesville marks the return to full capacity of the first of three lines to be restarted at the smelter. More than 125 employees have been hired, with almost 300 to be added by early next year.

Century closed three lines and laid off about 320 workers at the smelter in 2015 in a dispute over electricity prices. The company says it has operated at 40 percent capacity for the last three years.

Century is investing more than $150 million to upgrade smelting technology and train employees to use new equipment.

The smelter produces aluminum that supplies the defense and aerospace industries.