Abstract: At approximately 8:30 p.m. on October 29, 2003, an explosion occurred at a Hayes Lemmerz International, Inc. plant that manufactured cast alloy aluminum wheels. On the day of the explosion, a fire occurred in the chip-melt exhaust duct of furnace #5. As is common practice in the plant, when an aluminum fire occurs in the exhaust duct, the ventilation system is turned off to allow the fire in the duct to self-extinguish. After the ductwork had cooled down the ventilation system was started up again, and a fireball and pressure wave came through the system ductwork and back into the building from the chip-melt area of furnace #5. The fire lofted and ignited additional aluminum dust that had accumulated on rafters and equipment in the plant. The fire spread throughout the plant. One employee was killed and six others were injured. Two of the six injured employees were hospitalized, and the other four employees were transported to an emergency care facility and released after treatment.