Which section of the NFPA 704 system indicates health hazards?

The correct choice is blue, as this color in the NFPA 704 system specifically indicates health hazards. The NFPA (National Fire Protection Association) 704 system is a color-coded system used to quickly convey information about the hazards associated with materials. It uses a diamond shape divided into four quadrants, each representing a different hazard type: health (blue), flammability (red), reactivity (yellow), and specific hazards (white, often depicted around the diamond).

In the blue quadrant, the numbers range from 0 to 4, indicating the severity of health risks; a higher number indicates more severe health risks associated with exposure to the material. This allows first responders and others to quickly assess the potential danger that a substance may pose in terms of health.

The other colors represent different hazards: red signifies flammability, yellow indicates reactivity, and green is not used in the NFPA 704 system. This clear coding system is essential for safety and effective emergency response, making it vital to understand which color corresponds to which type of hazard.