A guest student was weighing out less than 200 mg of sodium hydride. The material reacted with moisture in the air, producing hydrogen. The heat of the reaction ignited the hydrogen on the end of the spatula being used to transfer the material and at the mouth of the bag holding the stock material (approximately 48 to 50 g). The student attempted to smother the flames with a cotton lab coat hanging nearby. He quickly determined that the lab coat was insufficient to smother the flames and entered the adjoining lab to get a fire extinguisher and warn other lab workers in the area. The other lab workers exited the lab, warned others in the area, pulled the fire alarm and called the laboratory shift supervisor. The student extinguished the fire with the fire extinguisher, then left the view more