In the NIOISH Pocket Guide, which item is NOT listed among the contents?

• A. Ionization potential
• B. Chemical formula
• C. Atomic radius
• D. Lower explosive limit

Answer: (C)

Atomic radius. A pocket guide for field use focuses on quick-reference, safety-relevant and identifiability information—things you’d need on the job. Ionization potential, chemical formula, and lower explosive limit all relate to hazard assessment, identification, or how a substance behaves in exposure or chemical reactions, making them practical inclusions. Atomic radius is a fundamental, theoretical property of atoms, not something you typically rely on for immediate safety decisions or operational tasks, so it wouldn’t be listed among the pocket guide contents.