Final answer:
In the NFPA Diamond, the Blue diamond indicates the health hazard level of a chemical. It is part of the NFPA 704 Hazard Identification System and is rated on a scale from 0 to 4, with 4 representing extreme health hazards.
Step-by-step explanation:
The Blue color in the NFPA Diamond represents the health hazard associated with a chemical. This part of the NFPA 704 Hazard Identification System communicates potential health risks to people who may be exposed to the chemical. The health hazard is evaluated on a scale from 0 to 4, with 0 indicating no significant health hazard, and 4 signifying a severe risk that could cause death or serious injury with very short exposure.
The other colors in the NFPA Diamond have their specific meanings - Red indicates a fire hazard, Yellow designates reactivity, and White signals specific hazards such as oxidizers, corrosives, or water-reactive substances.
In the NFPA Hazard Identification System, the blue diamond stands for the health hazard. This is rated on a scale from 0 (no hazard) to 4 (extreme hazard).