Dozens of people have been injured in an explosion at Imperial Sugar Co., a sugar refinery in Port Wentworth, in the U.S. state of Georgia, Thursday.

The explosion occurred at around 7:20 p.m. in a silo where refined sugar was stored until being packaged, Chief Executive of the company, John Sheptor said, according to the BBC News. More than 120 employees were working at the time of the explosion.

“As far as we know, it was a sugar dust explosion,” he said.

The blast sent flames shooting more than 100-feet into the air and was responsible for a partial collapse of the plant.

No deaths have been reported so far, but officials say at least 40 people are severely injured and the accident has sent authorities into a nearby river to reach for possible victims. However, local media centers had been notified by the Georgia Emergency Management Agency to expect as many as 100 injured people. Six employees were thought to be missing.

Most of the employees who were treated in local hospitals suffered critical burns.

“We’ve seen people that have had burns to their hands all the way to about 80 to 90 percent of their body,” Dr. Jay Goldstein of Memorial University Medical Center said quoted by local media sources.

The fire was so intense that a portion of the Savannah River and the Port of Savannah were closed. The river was shut down to ship traffic while the it was searched for possible victims.

“All I know is, I heard a loud boom and everything came down. When I got up, I went down and found a couple of people and we climbed out of there from the third floor to the first floor. Half of the floor was gone. The second floor was debris, the first floor was debris. All I could do when I got down was take off running,” uninjured Nakishya Hill, a machine operator told the Associated Press.

More than 100 police and firefighters came to the scene and a triage was set up to treat the wounded, who were loaded onto ambulances.