The bodies of three people were found and a further three people were presumed dead in a massive explosion that injured dozens more at a sugar refinery in the south-eastern state of Georgia, authorities said Friday according to DPA. More than 60 people were injured and 15 remained in critical condition with severe burns after the blast, which occurred Thursday night near the city of Savannah. The fire had been contained but not yet extinguished by Friday morning. Police said efforts to rescue the missing had been halted. "This has really shifted from a rescue operation to a recovery operation," Savannah-Chatham County Police Chief Michael Berkow said in broadcast remarks. Savannah Fire Department officials said the explosion happened Thursday in the bagging section of the factory. An investigation into the cause of the blast was ongoing, but authorities speculated that sugar dust from the refining process may have ignited.