The ERG Yellow Pages are organized by which criterion?

• A. Listed by UN number
• B. Generic safety procedures
• C. Name alphabetically
• D. Emergency response contacts

Answer: (A)

The key idea is that the Yellow Pages in the ERG are indexed by UN numbers. UN numbers are universal identifiers assigned to hazardous materials for transport, so they provide a consistent way to identify a substance even if multiple names exist. By looking up the UN number, a responder can quickly find the exact material entry and then use that to access the corresponding initial actions in the orange section or the detailed data in the blue pages. This UN-number organization keeps lookup fast and language-independent, which is crucial in emergencies. If you tried to organize by common name or generic procedures, you’d run into ambiguities and slower identification, especially in the chaos of a real incident.