The body was found near the silos used to store sugar after crews shored up the plant's wobbly remnants, Fire Chief Greg Long said. Three workers and a supervisor were believed to be missing, but it was not clear whether the body was that of a worker or the supervisor.
"We operate on the policy that everyone is alive until we get to them," he said.
The search was expected to be suspended for the night, and resume again Sunday.
Crews re-entered what's left of the Imperial Sugar Co. refinery after stabilizing the upper floors of a four-story building. They needed access to that building to gain entry to an 80-foot silo that rescuers wanted to search for the men, Long said.
Earlier Saturday, Long said firefighters all but extinguished the fire that had raged in the refinery since the explosion, allowing teams to resume searching for the missing men.
"We have an idea of where they are," Long said. "We didn't want to collapse anything."
The chief said he strongly believed the four men -- three workers and a supervisor, all of whom Long said he knew personally -- were the only people still unaccounted for from Thursday's blast.
Crews brought in heavy equipment Saturday to remove debris as investigators looked for the cause of the blast that ignited a storage silo. At least four flatbed trucks carrying segments of a giant crane and other machinery rolled through the refinery's front gates.
Imperial Sugar was one of the largest and oldest employers in this tiny city of 5,000 just a few miles west of Savannah. The vast refinery was a network of warehouses, silos and buildings eight stories tall connected by corridors of sheet metal.
Imperial President and CEO John Sheptor said sugar dust in a silo used to store refined sugar before packaging likely ignited like gunpowder. Sugar dust can be combustible if it's too dry and builds up a static electric charge.
The result was as devastating as a bomb. Floors in the plant collapsed, flames spread throughout the refinery, metal girders buckled into twisted heaps and shredded sheet metal littered the wreckage.
More than 30 employees were rushed to hospitals. Several were taken to a burn center in Augusta, 130 miles up the Savannah River. Many were in critical condition, including some who were placed on ventilators, said Dr. William Wessinger, the medical director at Memorial University Medical Center in Savannah. A spokeswoman from the Savannah hospital said Saturday that the last of nine workers treated there had been released.
Beth Frits, a spokeswoman for the Joseph M. Still Burn Center at Doctors Hospital in Augusta, said Saturday that 16 fire victims transferred from Memorial were in critical condition and three were in serious condition.
Company officials refused to speculate on when the plant might reopen, saying structural engineers needed to examine the damage.
More than 300 dust explosions have killed more than 120 works in grain silos, sugar plants and food processing plants over the past three decades. Most are preventable by removing fine dust as it builds up, experts say.