Abstract: On June 19, 2009, Employee #1 was operating a brass sorting machine at a Gun Room store warehouse where bullet casings were reconditioned. While standing in front of the machine, she activated it and dropped several used bullet casings (brass and aluminum) into the machine's hopper. When residual smokeless gun powder in the machine ignited, a flash fire occurred. Employee #1 was hospitalized at UC Davis Medical Center for second-degree burns over 20 percent of her body. Employee #1 had used this machine several hours per day for the previous 4 months. The hopper had shelves in it that were each sized to receive only a single-size cartridge. The hopper would vibrate, causing the casings to transfer outward into various shelves. The casings would then drop down a hole into holding containers. Similarly, unused or undetonated smokeless gun powder would fall out of the casings onto a surface where they would transfer to the outside edges and fall through small holes into containers below. The machine would routinely be covered by a light dusting of smokeless gunpowder, graphite, and paper dust. The sorting portion of the machine was more than 40 years old and its size was 33 in. high, 28 in. wide, and 40 in. deep. The employer had assembled this machine from several others to make a single prototype machine. During the incident, the machine was being operated on a trial basis. There were several different factors that led to the fire. Being built on site and experimental, the machine was not tested or listed prior to use. There were several sources of ignition sources on or near the unit including: an electric motor that was not intrinsically safe, a switch box with a light that was not intrinsically safe, loose electric snap-on connections in the vibrating unit, a vibrator mechanism that was not intrinsically safe, and impact/shock-sensitive bullet primers in the hopper and on the floor nearby.