SAVANNAH, GA. — The U.S. Chemical Safety Board on Sept. 24 said a Feb. 7, 2008, explosion at Imperial Sugar Co.’s Port Wentworth, Ga., refinery that killed 14 workers resulted from "ongoing releases of sugar from inadequately designed and maintained dust collection equipment, conveyors, and sugar handling equipment."

The report, which was issued following a 19-month investigation by the C.S.B., claims Imperial Sugar likely could have prevented the explosion with routine housekeeping. Release of the report sent Imperial Sugar’s share price into a tailspin, falling as much as 26% in trading on Sept. 24.

"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," said John Vorderbrueggen, the investigation supervisor at the C.S.B. who led the 19-month investigation.

According to the C.S.B.’s report, the initial explosion likely occurred inside a sugar conveyor located beneath two large sugar storage silos. The conveyor recently had been enclosed with steel panels creating a confined, unventilated space where sugar dust could accumulate to an explosive concentration. The C.S.B. said the sugar dust inside the enclosed conveyor then likely was ignited by an overheated bearing, causing an explosion that traveled into the adjacent packing buildings, dislodging sugar dust accumulations and spilled sugar located on equipment, floors, and other horizontal surfaces. Subsequently, a number of secondary dust explosions occurred, killing 14 workers and injuring 36 others, many with life-threatening burns.

The C.S.B., which is an independent federal agency that does not issue citations or fines, proposed a series of safety recommendations for Imperial Sugar to consider, including complying with National Fire Protection Association recommended practices for preventing dust fires and explosions, developing dust training and housekeeping programs, and improving its evacuation procedures. The C.S.B. report also called on industry groups AIB International and the American Bakers Association to develop combustible dust training and auditing materials.

Responding to the C.S.B.’s findings, John Sheptor, president and chief executive officer of Imperial Sugar, said the company collaborated with the C.S.B. throughout its investigation.

"We appreciate their professionalism and we value their contributions to our combustible dust and safety program," Mr. Sheptor said. "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 C.S.B. and industry."

Mr. Sheptor said the C.S.B.’s recommendations "are excellent guidance for the control and management of combustible dust," adding that Imperial "accepts the C.S.B. recommendations and is working diligently to implement them as part of our safety improvement initiatives."

"We have listened to the C.S.B. and other experts during the past 20 months and used their guidance in the reduction of risk in all of our operating sites," he said. "We hope that all companies that share the risk of combustible dust also will heed the insights of this report."

A public meeting to discuss the final report was set for Sept. 24 at the Hilton Savannah Desoto hotel in Savannah.