Under the NFPA 704 system, which position indicates reactivity?

In the NFPA 704 system, the numbers represent a color-coded system on a placard that communicates the hazards associated with materials. The system uses a diamond shape divided into four quadrants, each of which indicates a specific type of hazard: health (blue), flammability (red), reactivity (yellow), and specific hazards (white).

The reactivity hazard is indicated in the yellow quadrant, which is the bottom right position of the diamond. This position is designated for reactivity and is rated on a scale from 0 to 4, with higher numbers representing greater levels of reactivity to heat, pressure, or water.

In this case, positioning the number 4 in the yellow section communicates extreme reactivity, helping first responders quickly assess the potential dangers associated with the material in question. Understanding this system is crucial for effective hazard communication during emergency response situations, particularly when dealing with chemicals that can pose significant reactive risks.