What Does The Blue Field On An NFPA 704 Symbol Represent?

What Does The Blue Field On An NFPA 704 Symbol Represent? The National Fire Association (NFPA) has developed a color-coded number system called NFPA 704. The system uses a color-coded diamond with four quadrants in which numbers are used in the upper three quadrants to signal the degree of health hazard (blue), flammability hazard (red),