What does a P following the guide number indicate?

What does a P following the guide number indicate?

• A. Material stabilizes
• B. Material polymerizes
• C. Material reacts with water
• D. Material is explosive

Answer: (B)

A P after the guide number signals a polymerization hazard. Polymerization is when small molecules join together to form larger chains, and this process can run away if initiated or heated, releasing a lot of heat and gas. That rapid heat buildup and pressure can cause containers to rupture or explode, so seeing a P means you must treat the material as capable of polymerizing and handle it with extra caution—avoid heat and contamination, and be prepared for a potentially exothermic runaway reaction. Other hazard indicators point to stabilization, water reactivity, or explosive risk, but the P specifically identifies the polymerization tendency.

A P after the guide number signals a polymerization hazard. Polymerization is when small molecules join together to form larger chains, and this process can run away if initiated or heated, releasing a lot of heat and gas. That rapid heat buildup and pressure can cause containers to rupture or explode, so seeing a P means you must treat the material as capable of polymerizing and handle it with extra caution—avoid heat and contamination, and be prepared for a potentially exothermic runaway reaction. Other hazard indicators point to stabilization, water reactivity, or explosive risk, but the P specifically identifies the polymerization tendency.