Unable to turn a profit due to high energy costs and dropping commodity prices, a Kentucky Aluminum plant is going to temporarily halt production and lay off more than 600 workers.

Century Aluminum, the second largest employer in Hancock county, is shutting down its Hawesville smelter for 9-12 months. The plant has 628 employees.

According to county officials, the plant is not sure it will reopen the smelter after that, due to the high energy costs.

Century Aluminum says of the facility, that it is its largest “U.S. smelter and the largest producer of high purity primary aluminum in North America.”

Recently, the plant had increased production, and added 60 jobs just in April.

Andy Meserve, president of United Steelworkers Local 9423, said, “We celebrated that. I guess if it hadn’t been for the cost of power, we would still be rocking and rolling.”

Employees were notified on Wednesday of the pending layoffs.