UNITED STATES
DEPARTMENT OF LABOR

Employee #1 was cleaning a pyrotechnic mixture out of a small Murphy-Rogers, Inc., dust collector with a top-mounted vacuum fan. He had removed the six filter cartridges from the machine and was standing at the side of the 30 in. by 28 in. opening as he attempted to dislodge some loose compound--a mixture used for roadway flare and primer ignition--from the interior of the collector. The material ignited and Employee #1 suffered first- and second-degree burns. The chemical compound involved was a basic fuel and oxidizer mixture in common, long term use in the fuse-and-hand held signal flare industry. The material being collected by this dust control system was the airborne fines generated when dry material was mixed by hand. This unit had last been cleaned in 1996, at which time a filter cartridge that was removed from the collector ignited while it was being cleaned, causing minor injuries to the employee working on it at the time. The basic mixture had been tested both prior to and following the accident for static and impact ignition hazard, and no hazard was detected by the testing facility. While the cause of the ignition had not been identified, a pyrotechnic expert suggested that the age of the chemicals in the collector might have been a cause, or that the chlorate had broken down and was in the collector. Possible sources of ignition were static discharge or impact. A static resistant plastic spatula was in Employee #1's right hand at time of ignition. PPE in use were cotton coveralls, light weight Plastisol-coated gloves, safety glasses with side shields, and a disposable dust mask. Employee #1 was wearing sneakers. No additional PPE in use. The dust collector was grounded and a fiberglass ladder was being used.