In NFPA placards, the letter P indicates

• A. Potential for polymerization
• B. Pressure hazard
• C. Physical hazard
• D. Polarity hazard

Answer: (A)

The white area of an NFPA 704 placard carries special hazard letters to flag risks not shown by the numeric health, flammability, and reactivity ratings. The P symbol signals a polymerization hazard, meaning the material can polymerize under certain conditions—often exothermically and potentially releasing gases or increasing pressure. This warning tells responders to avoid conditions that could trigger polymerization (such as heat, contamination, or incompatible substances) and to follow any storage or handling guidance (like using inhibitors or stabilizers as specified) to prevent a runaway reaction. This focus on the material’s tendency to form polymers is why the polymerization interpretation is the correct reading of the symbol.