COLUMBIA, S.C. -- A diesel generator plant in South Carolina plans to add up to 500 jobs in the next four years.

Caterpillar said on Tuesday that it plans to more than triple employment at its plant in Newberry. Caterpillar spokesman Jim Dugan said the company has 190 workers now.

Dugan said the hiring could start late this year, with hiring based on the economic recovery. He said that Caterpillar is transferring generator work done at its Griffin, Ga., plant to the Newberry facility. He said that will allow the Georgia plant to concentrate on making engines.

The Newberry plant makes generators used in larger homes, stores, farms and cell phone towers.

The company also has an engine plant in Greenville, a parts facility in Sumter, a re-manufacturing plant in Summerville and a logistics operation in Fountain Inn.