Firefighters, police and media crews evacuate the immediate area of the fire for a 1/2 mile zone amid fears that tanks of flammable materials including propane tanks, might explode. The massive fire at a chemical plant outside Atlanta on May 23, 2014, prompted the evacuation of hundreds of people from nearby businesses and spewed black plumes of smoke that were visible from miles away.

MARIETTA, Ga. - A massive fire at a chemical plant outside Atlanta on Friday night prompted the evacuation of hundreds of people from nearby businesses and spewed black plumes of smoke that were visible from miles away.

The smoke was determined to be nontoxic and posed no threat to residential areas, said Marietta Police Officer David Baldwin. He said businesses were evacuated and sections of nearby Cobb Parkway closed to help crews contain the fire and prevent it from spreading.

More than 25 trucks joined in the firefighting effort, which was still active late Friday night, more than three hours after the blaze began.

Baldwin said the warehouse is owned by AmRep, described on the company's website as a specialty chemical manufacturer and packager. No one answered a telephone number listed for the company's corporate headquarters Friday night.

Baldwin said explosions were heard in the building, due to the chemicals stored inside.

There were no reports of injuries and no indication that anyone was inside the warehouse when the fire began Friday evening.