A large fire burned Monday inside a chemical plant on the coast of Georgia, where authorities ordered about 100 nearby homes to evacuate because of threats from toxic smoke and potential explosions.

Emergency responders safely evacuated a small handful of employees working when the fire broke out at about 4 a.m. Monday at the plant outside the port city of Brunswick, Georgia, said fire Capt. Eric Prosswimmer, who was on the scene with fire crews from Jacksonville, Florida, sent to help battle the flames.

The fire sent a large plume of thick smoke into the air from the plant, located located about 70 miles (113 kilometers) south of Savannah.

As a precaution, local emergency officials ordered neighborhoods within a 1-mile (1.6 kilomter) radius of the plant to evacuate. People within a 3-mile (5-kilomter) radius were told to shelter in place.

Wayne Neal, chairman of Glynn County's elected Board of Commissioners, estimated roughly 100 households had been told to evacuate. Sheriff's deputies were using patrol cars to block entrances to affected neighborhoods.

Smoke from the plant had largely died down by late morning. But fire still burned inside, Prosswimmer said, and changing winds could stir up more smoke.

Hazardous materials crews were working to survey the threats to determine whether evacuations should cover a larger area.

"We will evacuate more than we need to evacuate," Prosswimmer told a news conference. "I know it's a big inconvenience to the people, but it's the right thing to do for health and safety reasons."

Officials said they were mostly concerned about hazards posed by smoke drifting into populated areas. There had also been explosions at the site.

Prosswimmer said heat from the fire had caused three metal tanks containing chemicals to explode. Fighting the blaze was further complicated when firefighters depleted more than 1 million gallons (3.8 million litres) of water stored in tanks on the site.

Prosswimmer said firefighters had backed away from the fire to await the arrival of tankers carrying more water to the scene.

"We're going to take very calculated, slow steps at this and make sure no one's in jeopardy," Prosswimmer said, adding: "Right now we're staged way far back from it and some of it's just being allowed to burn."

He said one firefighter suffering from exhaustion had been taken to a hospital and was in stable condition. There were no other injuries.

The plant is operated by Symrise, a German company that produces fragrances, flavoring and other ingredients for foods and cosmetics. The Georgia plant manufactures fragrance ingredients used in perfumes, detergents and household cleaners, said Smyrise spokesperson Christina Witter.

The company said in a statement Monday the cause of the fire was not known.

"Currently, Symrise has no reason to believe that the fire will cause additional health hazards to the local community," Symrise's statement said. "Symrise will closely cooperate and support local authorities in analyzing the causes for the fire as soon as the authorities allow return to the area."

Prosswimmer said an investigation would be conducted after the fire was extinguished.