Sugar Company Ignored Explosion Hazards, Investigation Concludes

The U.S. Chemical Safety Board's (CSB) investigation into the cause of a fatal 2008 explosion at a Georgia sugar refinery concludes that the Imperial Sugar Company and its managers did not take corrective actions to prevent dust explosions, even though they knew of potential hazards. The initial blast and subsequent dust explosions throughout the plant killed 14 workers and injured 36.

On the evening of Feb. 7, 2008, an enclosed, unventilated conveyor belt under two storage silos exploded in the Port Wentworth, GA, plant owned by Imperial Sugar. According to the Investigation Report [1] produced by the CSB:

"The explosion lofted sugar dust that had accumulated on the floors and elevated horizontal surfaces, propagating more dust explosions through the buildings. Secondary dust explosions occurred throughout the packing buildings, parts of the refinery, and the bulk sugar loading buildings. The pressure waves from the explosions heaved thick concrete floors and collapsed brick walls, blocking stairwell and other exit routes."

The report lists a variety of causes of the explosion, including poor design and maintenance of equipment, poor "housekeeping practices," and inadequate emergency evacuation plans and communications. Although dust collection systems and ducts to transport the collected dust existed throughout the plant, a review of the dust-handling system conducted just prior to the explosion showed "the dust collection equipment was in disrepair, and some equipment was significantly undersized or incorrectly installed. Some dust duct pipes were found to be partially, and in some locations, completely filled with sugar dust."

The CSB is an independent federal agency that investigates industrial chemical accidents, reviews safety codes and regulations, and makes recommendations based on its investigations. It does not have the power to issue citations or fines.

The agency began investigating the incident the day after the accident and worked with various state and local agencies and Imperial Sugar personnel. The 19-month-long investigation was headed by CSB's John Vorderbrueggen. In the press release [2] announcing the final report, 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 notes that dust explosions have occurred in sugar plants since about 1925 and that Port Wentworth personnel were worried about the possibility of sequential explosions as far back as 1967, according to internal correspondence. (Imperial bought the Georgia facility in December 1997.) Despite a series of fires over nearly 40 years in Imperial Sugar plants, the CSB wrote, "that the small events and near-misses caused company management, and the managers and workers at both the Port Wentworth, Georgia, and Gramercy, Louisiana, facilities to lose sight of the ongoing and significant hazards posed by accumulated sugar dust in the packing buildings. Imperial Sugar management and staff accepted a riskier condition and failed to correct the ongoing hazardous conditions, despite the well-known and broadly published hazards associated with combustible sugar dust accumulation in the workplace."

In 2006, the CSB recommended to the Occupational Safety and Health Administration (OSHA) that OSHA issue a combustible dust standard generally for industries that face dust-related workplace hazards. OSHA did not begin a rulemaking but issued a National Emphasis Program (NEP) in 2007 that directed federal inspectors to increase inspections at plants that could be subject to dust explosions and that were already subject to certain OSHA requirements. The NEP does not impose a new combustible dust standard, however, or impose additional requirements on industry.

In 2008, OSHA issued 211 citations for violations at the company's Georgia and Louisiana plants, resulting in $8.7 million in initial fines, according to a Sept. 24 Associated Press article [3]. The company is appealing the fines, and OSHA has set a hearing to resolve the issue for May 2010, according to a Savannah Morning News article on April 4. The article [4] also notes a 2008 study by the Senate Health, Education, Labor and Pensions Committee criticizing OSHA's tendency to collect a significantly lower level of fines than the amounts initially levied against violators.

OSHA announced on April 29 that it would begin a combustible dust standard rulemaking as the CSB urged the agency to do in 2006. In the press release [5] announcing the intent to issue an advanced notice of proposed rulemaking (ANPRM), Secretary of Labor Hilda Solis said, "OSHA is reinvigorating the regulatory process to ensure workers receive the protection they need while also ensuring that employers have the tools needed to make their workplaces safer." The release specifically cites the CSB's consistent message that a broad combustible dust standard is necessary.

On Sept. 25, OSHA submitted the ANPRM [6] to the Office of Information and Regulatory Affairs for review. The ANPRM is expected to cover issues such as data collection, dust hazard assessment, and a discussion of different regulatory approaches. The rule would seek to broadly establish a combustible dust standard potentially across metal, wood, plastic, rubber, coal, flour, sugar, and paper industries. The submission summary notes OSHA's intent to have a stakeholders' meeting in December. OSHA is notoriously slow to produce rulemakings, and the breadth of the industries covered could mean it will be years before a standard is completed. The CSB report says that OSHA's NEP for combustible dust will remain in place until a new standard is complete.

In the meantime, the CSB made a series of recommendations to Imperial Sugar, its insurance company, and others, encouraging them to use similar regulations in place for other industries with comparable hazards to reduce the risk of major accidents. The recommendations to Imperial Sugar include implementing a corporate-wide "housekeeping program" to control dangerous dust accumulation, developing training materials that focus on dust hazards, and improving emergency evacuation policies and procedures.

The Georgia plant was rebuilt and began operating again in June.

Image in teaser by flickr user David Sledge [7], used under a Creative Commons license.