Fire at chemical plant sends huge plume of smoke into the sky in US state of Georgia

A huge plume of black smoke pouring into the sky from a fire at a chemical plant in the US state of Georgia has forced evacuations - as scientists try to establish what it contains.

The fire ignited when a sprinkler head malfunctioned at the BioLab plant in Conyers, around 25 miles from the city of Atlanta, on Sunday morning.

This caused water to mix with a chemical, prompting a reaction that produced the plume, Rockdale County fire chief Marian McDaniel said.

It's not yet known which chemicals were contained in the smoke.

"We are actively responding to an occurrence at our facility," a BioLab representative said in a statement.

"Our employees are accounted for with no injuries reported. Our team is on the scene, working with first responders and local authorities to assess and contain the situation."

With the smoke billowing behind him, Sheriff Eric Levett said the fire had been initially contained but had reignited and firefighters were dealing with the smoke.

He said that some areas were being evacuated and warned people to stay away from the area.

Interstate 20 was shut down in both directions in the area, the Georgia Department of Transportation said in a post on X.

The federal Environmental Protection Agency and the Georgia Environmental Protection Division were both at the scene to monitor the air and identify what the plume consists of.

Firefighters were working on removing the chemical from the building, away from the water source, the fire service said.

Once the product is contained, the situation will then be assessed and residents will be informed when it is safe to return to their homes, Ms McDaniel said.