PORT WENTWORTH, Georgia (CNN) -- Firefighters recovered a fifth body Saturday from the ruins of a sugar refinery near Savannah, Georgia, gutted by a massive explosion and fire Thursday night, authorities said Saturday.
Firefighters found the fifth body on the third floor of the Imperial Sugar refinery's main building, near silos used to store sugar, Port Wentworth Fire Chief Greg Long said.
He did not identify the individual.
Firefighters entered that main building -- used for processing and packing sugar -- earlier Saturday after they used heavy equipment to shore up its shaky remains. The top floor had collapsed onto the third, Long had said, and they were trying to prevent that floor from falling onto the second.
He said firefighters had to enter that main building to search three silos, which stand side-by-side behind it.
Earlier, a fire official said firefighters must shore up floors to get to key locations Saturday in their search.
Search and rescue operations were expected to be suspended as dusk fell, Long said, although he said fire operations would likely continue through the night.
The bodies of four other employees were discovered Friday at the site, located in Port Wentworth, Georgia, just northwest of Savannah..
At least three workers remain missing since the disastrous blast and fire on Thursday.
Firefighters were still putting out fires Friday night, and debris still smoldered, Long said. Watch firefighters at the scene »
Twenty workers who were burned in the fire remained hospitalized Saturday in Augusta, Georgia, said Dr. Fred Mullins, medical director of the Joseph M. Still Burn Center.
Seventeen were in critical condition, including one being treated at the Medical College of Georgia -- also in Augusta.
The remaining three patients at Still Burn Center were expected be to upgraded from serious condition later Saturday, Mullins told reporters.
The first patient from the blast may be released Sunday, he said. Some of the workers suffered deep burns to their faces and extremities.
Mullins said the center was in need of blood.
"Prayers and donating blood are probably most important."
Most of the patients suffered burns over at least 30 percent of their bodies; one was at 95 percent, a hospital spokeswoman said.
Mullins said most of the patients were in a medically induced coma because they were on ventilators. Some of the burn victims could be hospitalized for as long as six months, then face more months of outpatient treatment and reconstruction surgery, he said.
The burn victims were airlifted from Savannah, said burn center spokeswoman Beth Frits. The victims, mostly men, range in age from 18 to 50.
Frits said there were about 100 workers in the plant at the time of the blast, and more than 40 escaped injury.
Officials said the fire may have started by sugar dust igniting, possibly in a room where workers were bagging sugar.
The fire burned three or four large warehouses and rooms, said Capt. Matt Stanley, spokesman for the Savannah Fire Department.
"Right now we have no indication that there's been any wrongdoing or any criminal act," said Phil Durham of the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives.
The bureau will help investigate the fire.
The plant is the major employer in the suburban town of Port Wentworth.
On Saturday, the company's chief executive officer, John Sheptor, said all employees were receiving pay and benefits during the period of "concern and investigation." E-mail to a friend