The NFPA hazard identification label is in the form of a large diamond that contains four smaller diamonds of different colors. It was created to quickly alert firefighters and other emergency personnel arriving on the scene of a fire to the risks associated with hazardous chemicals in the area so that appropriate precautions could be taken. The different colored diamonds that make up the large diamond indicate:
- Health hazards (blue diamond)
- Fire hazards (red diamond)
- Reactivity (yellow diamond)
- Special hazards related to a chemical (white diamond)
A numbering system from 0 - 4 indicates the severity of each health, fire, and reactivity hazard, with "0" indicating no hazard and "4" indicating the most severe hazard.
The white diamond at the bottom of the NFPA symbol is the special hazard section.
- If the chemical reacts with water, a strike-out W (
W) will appear in this section.
- OX means the chemical is an oxidizer.
- COR means the chemical is corrosive.
- The radioactivity symbol indicates that the chemical is radioactive.
Some laboratories may use this diamond system to label secondary containers of hazardous chemicals that remain in the laboratory.