What hazard does the red section of the NFPA 704 placard represent?

The red section of the NFPA 704 placard specifically indicates flammability hazards. This color-coded system is designed to communicate the level of risk associated with different materials quickly and effectively. The red zone is graded on a scale from 0 to 4, where 0 represents a substance that will not burn under any conditions, while 4 indicates a material that can easily ignite and burn rapidly. Understanding this aspect is crucial for emergency responders and others who handle hazardous materials, as it provides immediate visual information about how to approach a fire or other flammable risks associated with that substance. Each color on the NFPA placard represents a different type of hazard, which is why the other options relate to different hazards that are not shown in red.