How many colored hazard diamonds does the National Fire Protection Association 704 system use in its placards?

The National Fire Protection Association (NFPA) 704 system uses a colored hazard diamond with four quadrants. Each quadrant represents a different type of hazard: blue for health risks, red for flammability, yellow for reactivity, and white for specific hazards. The diamonds are used to provide quick visual information about the dangers associated with materials.