A report from the U.S. Chemical Safety Board shows a spark from static electricity caused an explosion and fire that destroyed a chemical warehouse in Des Moines last year. One worker suffered minor injuries in the October 29, 2007 incident at Barton Solvents .

Lead investigator Randy McClure says the worker was transferring the flammable liquid ethyl acetate to a portable steel tank. "In the process of transferring this material, there was a static electric spark that occured somewhere around the mouth of the tote and ignited the vapor that was accumulating around that opening," McClure said.

Workers tried unsuccessfully to extinguish the fire, which eventually engulfed the warehouse and sent 55 gallons drums flying more than 100 feet in the air. McClure says workers in the plant were not using equipment designed for flammable liquid service. The equipment was not bonded or grounded to prevent the build up of static electricity.

"When we reviewed the manufacturer’s literature, it was really clear that the manufacturer of this equipment never intended for it to be used like it was being used," McClure said. "It was a really unsafe activity that was going on."

The fire in Des Moines happened just three months after a similar explosion destroyed a Barton Solvents facility in Wichita, Kansas. That incident was also blamed on a static spark and improper bonding and grounding.