PORT WENTWORTH, Ga. — Firefighters recovered three bodies in the wreckage of a sugar refinery today leveled by an explosion overnight and believed they knew where three others lay, police and fire officials said.

Crews found three bodies in tunnels beneath the building, which was reduced to a mass of rubble, twisted beams, and mangled metal in the blast late yesterday, Georgia Insurance and Safety Fire Commissioner John Oxendine said. They were trying to reach the remains of at least three others, he said.

Identities of the dead were not immediately available.

Police Chief Michael Berkow of Savannah-Chatham County told families of missing workers that rescue efforts at the massive Imperial Sugar Company refinery had shifted to recovery operations hours after the explosion. Dozens of the nearly 100 people were working inside at the time of the blast were hurt, many critically burned.

Officials suspect sugar dust, which can be volatile, as the cause of the explosion.

“There was fire all over the building,” a machine operator who escaped from the third floor of the refinery on the Savannah River, Nakishya Hill, said.

“All I know is, I heard a loud boom and everything came down,” Mr. Hill, who was uninjured except for blisters on her elbow, said. “All I could do when I got down was take off running.”

The blast was felt by residents throughout the Savannah suburb.

Police Lieutenant Alan Baker and his wife, Joyce, told CNN they were among the first on the scene. Lieutenant Baker said he went with a maintenance worker to turn off a gas main while his wife, a Red Cross first aid instructor, treated the injured.

“It was like walking into hell,” Joyce Baker said. “We had approximately 13 men who were coming out and they were burned, third-degree burns on their upper bodies. And they were trying to sit down and the only thing that they wanted was to know where the friends were.”

Some of the burned men had “no skin at all” and some had skin “just dripping off them,” Ms. Baker said.

More than 30 people were taken to hospitals, some airlifted to a burn center in Augusta, 130 miles up the Savannah River, according to police and hospital officials. Several were in critical condition, including some who were placed on ventilators, the medical director at Memorial University Medical Center in Savannah, Dr. William Wessinger, said.

A spokeswoman for the Joseph M. Still Burn Center at Doctors Hospital in Augusta, Beth Frits, said 15 fire victims transferred from Memorial were in critical condition and three were in serious condition.

The plant is owned by Imperial Sugar and is known in Savannah as the Dixie Crystals plant.