Abstract: Employee #1 was spreading a commercial carpet adhesive, D-9 Exterior Carpet Adhesive, in the doorway of the storage closet that was located in the hallway of the restroom. The adhesive was being spread in preparation for the laying of the carpet. Employee #1 had previously spread approximately five gallons of adhesive throughout the rest of the restroom. The main door to the restroom was open to provide ventilation, and there was no form of mechanical ventilation being used. The room where the glue was being used was an L-shaped room. The fumes from the adhesive built up and were ignited by the automatic gas-burning furnace that was located in an adjacent room to the restroom. When the fumes ignited, a flash fire and explosion occurred that caused the newly spread adhesive to ignite. Employee #1, who had a small amount of adhesive residue on his clothes and hands, sustained first-degree burns on his left leg and first and second-degree burns on his left hand. Employee #1 was working alone at the time of the accident.