Type "D" and Type "E" fires should only be handled by trained personnel. Type D fires include those involving powdered metal materials such as magnesium. A special powder is used to extinguish this type of fire.
A Type E fire is one that cannot be put out or is liable to result in detonation, if an attempt is made to put it out. When faced with this type of fire, trained personnel would usually allow it to burn out while protecting nearby materials.