MANCHESTER, Ga. (AP) — An explosion rocked a metals plant in west Georgia early Thursday, injuring seven people, authorities and witnesses said.

The explosion happened around 8:45 a.m. at G&S Metals in Manchester, about 60 miles south of Atlanta. About 20 workers were inside, Manchester Fire Chief Greg Lehtimaki said.

Truck driver Gary Highley, 62, of Wabash, Ind., said he was switching trailers when he heard the blast.

"I saw the roof blow up," he said. "That was enough for me to get out of there."