Inadequate housekeeping practices and the failure by company chiefs to take action despite being aware of the hazards were two major causes of the blast that ripped through the Georgia facility in February 2008, killing 14 workers and injuring 36 others, said the safety body in its final report released yesterday.
The CSB said the explosion resulted from ongoing releases of sugar from inadequately designed and maintained dust collection equipment, conveyors and sugar handling machinery.
“Inadequate housekeeping practices allowed highly combustible sugar dust and granulated sugar to build up throughout the refinery’s packing buildings,” CSB investigators concluded.
The primary blast occurred inside an unventilated sugar conveyor that allowed sugar dust to build up to “an explosive concentration”, explained the CSB. An overheated bearing was the likely spark that caused the explosion which triggered further blasts as it travelled into the adjacent packaging facility.
This dislodged huge accumulations of sugar dust resulting in “a powerful cascade of secondary dust explosions” that was responsible for many of the deaths and injuries as well as destroying the refinery’s packing operations.
CSB investigation leader John Vorderbrueggen, said, “Imperial’s management as well as the managers at the Port Wentworth refinery did not take effective actions over many years to control dust explosion hazards – even as smaller fires and explosions continued to occur at their plants and other sugar facilities around the country.”
The report laid bare a series of fallings on the part of the sugar giant – including internal correspondence from 1967 flagging up Port Wentworth manager’s fears over the possibility of a sugar dust explosion that could “travel from one area to another, wrecking large sections of a plant” – exactly what happened more than 30 years later at the refinery.
But the company failed to act even though “spilled sugar was knee-deep in places on the floor, and sugar dust had coated equipment and other elevated surfaces”, said the CSB.
"The explosion at the plant was entirely preventable and the deaths that occurred in February 2008 should never have happened,” said CSB chairman John Bresland.
The CSB tabled five recommendations – including urging Imperial Sugar to comply with National Fire Protection Association (NFPA) practices for preventing dust fires and explosions. The report also called on the firm to develop dust training and housekeeping programs, and improve its evacuation procedures. .
Industry groups AIB International and the American Bakers Association were further advised to develop combustible dust training and auditing materials
Imperial Sugar welcomed the report and said it accepted CSB’s recommendations.
“We have worked very hard to make our facilities the safest possible, and will continue to share what we have learned and will learn with the CSB and industry,” said CEO and president John Sheptor.
He added: “Imperial accepts the CSB recommendations and is working diligently to implement them as part of our safety improvement initiatives.”