Which section of the Emergency Response Guidebook (ERG) would a firefighter use when they know the chemical identification number of a hazardous material?

The correct choice is the yellow section of the Emergency Response Guidebook (ERG). This section is specifically designed for use when the chemical identification number of a hazardous material is known. The yellow section organizes entries based on the four-digit identification number assigned to the material, which allows responders to quickly find information related to that specific substance.

This feature is particularly useful in emergency situations where time is of the essence, as it enables firefighters and other emergency responders to access vital information, such as potential hazards, initial isolation and protective action distances quickly. The systematic arrangement of materials by their identification numbers streamlines the response process and enhances safety during hazardous material incidents.