NFPA704

The NFPA 704 standard, also known as the "hazard diamond" or "fire diamond," is a system developed by the National Fire Protection Association for the identification of hazardous materials. It provides a readily recognizable means for emergency responders to quickly assess the risks associated with a particular substance during a fire, spill, or other emergency. The system consists of a diamond-shaped symbol divided into four colored quadrants, each representing a different category of hazard. The top diamond, colored red, indicates flammability. The blue diamond on the left signifies health hazards. The yellow diamond on the right denotes instability or reactivity. The bottom white diamond is reserved for special hazards, such as oxidizers, water-reactivity, or simple asphyxiants.

Within the red, blue, and yellow diamonds, a numerical rating from 0 to 4 is used to indicate the severity of the hazard. A rating of 0 means there is no significant hazard. A rating of 1 indicates a slight hazard, while 2 suggests a moderate hazard. A rating of 3 signifies a severe hazard, and a rating of 4 denotes an extreme hazard. For example, a substance with a health hazard rating of 4 would be acutely toxic or capable of causing death or serious injury. The white diamond may contain specific symbols or abbreviations to further clarify special hazards, such as "OX" for oxidizer or "W" with a diagonal line through it to indicate a substance that reacts dangerously with water. NFPA 704 is primarily intended for use by firefighters and other emergency personnel and is not typically found on consumer product labels.