Investigators believe a fire that burned for hours in Clayton County started when items being stored in a metal basket ignited, officials said Thursday.

The fire at Tensar International, a company that makes petroleum-based products and plastics in Morrow, started around 2 p.m. Wednesday and took at least six hours contain. Several metro area fire departments helped battle the blaze, which produced thick, black clouds of smoke that could seen for miles.

Clayton County fire Chief Jeff Hood said Thursday a metal basket being moved to the site with chemical products started sparking and ignited about 30 seconds later. No one was seriously injured in the fire, but a firefighter sustained a leg injury.

The company's employees were assisting with cleanup Thursday afternoon as fire crews continued to douse remaining hot spots. Rows of scattered building parts were still at the site, blocked by barbed wire fence and caution tape.

A spokesman for Tensar said the company has not yet totaled its damages from the fire.

Area businesses on Citizens Parkway off Jonesboro Road were evacuated Wednesday afternoon as firefighters worked to prevent the fire from spreading.

Jonesboro Road, and the several car dealerships and stores along the strip, seemed to return to a state of normalcy Thursday afternoon.

Sylvia Hughes, 64, the controller at a Heritage Cadillac Saab dealership next door, said the dealership experienced minor setbacks because of the fire.

"Business was, needless to say, put to a halt for us," she said. "I looked out from my office and I couldn’t even see past our used car lot."

Donna Haan, 49, a customer service representative at the Sons Acura dealership across from Tensar, said while the area was on lockdown, customers got impatient.

"It looked like it was right on top of us," she said. "We had customers screaming over the phones because they were trying to get their cars. No one could come in or get out. Clayton County did a very good job of isolating the problem, though. They did a great job making everyone feel safe."