SAVANNAH, GA (WTOC) - Investigators with the US Chemical Safety Board are on the scene of the sugar refinery explosion in Port Wentworth. They're still early into the investigation and they say finding the ignition source that started the explosion may be "impossible."
Investigators with the U.S. Chemical Safety Board arrived in Port Wentworth just 18 hours after the explosion. More investigators are expected on Monday. The work is long and tedious, but U.S. Chemical Safety Board Investigations Manager Stephen Selk said it has never been more important.
"The tragic event that occurred here in Savannah demonstrates that the problem of dust explosions in the industry has yet to be solved," he said. "It is a problem that requires further attention."
Investigators believe a build-up of sugar dust triggered the explosion from the basement beneath two of the sugar silos. Selk explained that sugar dust is a combustible material. All that is needed is oxygen -- air. When the dust flies into the air, he said something as minor as static electricity can ignite an explosion in a confined area, even in the equipment designed to remove the dust itself.
"It can be ironic that ducting used for dust extraction and other equipment such as dust collectors can themselves be conducive for the initiation of dust explosions," Selk said.
Selk also said some equipment failed at the plant weeks before the explosion; however, it was too early to say if that may have led to the blast on February 7.
"We do have information that one segment, just one segment, of the system had experienced a problem in earlier weeks," he said, "but I cannot at this time relate that to the accident."
Selk said no one was injured in that explosion. They do not know all the details about what happened, but he said they were interviewing the company's managers.
Still, he said in many cases, one explosion can set off another.
"In such instances," he explained, "some primary event occurs that kicks up larger amounts of dust that may have accumulated and disperses the dust into the air. When this happens the stage can be set for catastrophe."
He added, "a very large, flammable dust cloud ignites with devastating consequences. In other instances, an initial explosion may simply propagate as the blast wave ahead of a rapidly advancing flame front, the fireball, which disperses more dust and ignites as the fireball expands."
The investigation is still in its early stages. The U.S. Chemical Safety Board is working with Imperial Sugar to go through the damaged areas and even disassemble them to try to figure out exactly what happened.
Over a 25 year period, Selk said more than 280 fires and explosions have killed 119 people and injured more than 700 others.