An explosion and fire of combustible dust at a Georgia sugar refinery Feb. 7 killed six workers and renewed concerns that industry safety standards for combustible dust are inadequate, Chemical & Engineering News reports. Five days after the accident, two workers remained missing, and hotspots continued to burn.

In all, 44 workers were injured, 20 of them severely enough to merit treatment at burn centers, including 17 who have been placed in "medically induced comas" because of the severity of their injuries from the accident at Imperial Sugar Co. at Port Wentworth, near Savannah, according to C&EN.

The exact cause of the accident remains unknown because the site is too unstable to allow entry except by rescue and fire personnel, said Michael Wald, a spokesman with the OSHA regional office in Georgia. The suspected explosive agent, however, is combustible dust — in this case combustible sugar dust. The Chemical Safety & Hazard Investigation Board (CSB) has dispatched four investigators to the site.

Following a CSB study released in November 2006 that found 281 dust explosions between 1980 and 2005 killed 119 U.S. workers and injured 718, CSB recommended that OSHA issue a general comprehensive combustible dust standard. The standard would address hazard assessment, engineering controls, housekeeping and worker training for all industries, and would be similar to OSHA regulations for the grain industry issued in the 1970s after a series of grain dust explosions, said Daniel Horowitz, a CSB spokesman.

OSHA instead announced in October 2007 a less aggressive "national emphasis program" for combustible dust, and in December began training its compliance officers to look for dust problems when conducting other inspections, said Wald. The agency's program identified industries that handle combustible dust, including sugar companies, but did not issue exact standards for OSHA inspectors to use to identify dust problems and to use to ensure safety compliance.

CSB called for OSHA inspection standards, according to Horowitz, including clearly identified and enforceable regulations. Without standards, he said, the burden is put on the inspector to show management that conditions are dangerous.