COLUMBIA, S.C. — The South Carolina company that employed four workers who died following an explosion as they unloaded fireworks in North Carolina was fined after a previous accident.

A 2001 explosion at Melrose South Pyrotechnics' plant near Rock Hill killed an employee and injured two other workers. The company agreed in a settlement with state workplace safety investigators to pay a reduced $20,000 fine without acknowledging any wrongdoing.

The company had been cited for a lack of training and improper storage.

Two Melrose South employees also were hurt during a fireworks show at Fort Stewart, Ga. two years ago.

The company said Monday it is working with officials to determine what caused the July 4 accident in North Carolina.