In the NFPA 704 system, what range of numbers represents the health hazard category?

The NFPA 704 system uses a numerical scale to indicate the severity of health hazards, with a range from 0 to 4. This scale is designed to provide a quick reference to the level of health risk associated with a substance. A score of 0 indicates no health hazard, while a score of 4 signifies a severe health risk that could be life-threatening or cause major injury upon exposure. This system is crucial for first responders and firefighters as it assists them in assessing risks quickly and effectively when dealing with hazardous materials.