What is the symbol used for materials that may polymerize under some emergency conditions?

• A. P
• B. A three armed fan
• C. NFPA symbol
• D. Date prepared

Answer: (A)

Polymerizable materials can rapidly form polymers when exposed to heat, friction, or contaminants, which can release a lot of heat and gas and potentially cause a container to rupture. The symbol used to warn about this specific hazard is the letter P. It signals to handlers that the substance may polymerize under stressful conditions, so care is needed to avoid initiating conditions that could start polymerization and to handle or store the material accordingly.

The other symbols aren’t specific warnings for this hazard. A three-armed fan isn’t a standard marker for polymerization risk, and the NFPA symbol is a general hazard indicator not devoted to signaling polymerizable substances. Date prepared isn’t a hazard symbol at all.