[6] Charlotte Fire Department is notable for its role in the development of NFPA 704, the "fire diamond" found on chemicals which depicts in a simple and clear manner the flammability, health hazards and reactivity of the substance.The crew tried to suppress the fire with water, which resulted in the vat exploding due to metallic sodium being stored in the kerosene.Thirteen firefighters were injured, several of whom had critical injuries while one lost both ears and most of his face from the incident.In this case, sodium was able to react with water to release hydrogen gas and large amounts of heat.Fire Marshal J. F. Morris developed the diamond-shaped placard as a marking system to indicate when a building contained hazardous materials.