What is the Emergency Response Guidebook primarily used for?

The Emergency Response Guidebook (ERG) is specifically designed to assist first responders during hazardous materials incidents. It serves as a vital resource for emergency personnel, providing immediate information about the substance involved, recommended safety measures, and initial response strategies. This enables responders to make quick, informed decisions to protect themselves, the public, and the environment when responding to emergencies involving hazardous materials.

The other options, while related to hazardous materials, do not capture the primary purpose of the ERG. For instance, shipping regulations are essential for compliance and safety during transport but fall outside the scope of the ERG's primary function. Similarly, training drivers is important for safe transportation practices but is not the focus of the Emergency Response Guidebook. Finally, documentation of transport is related to regulatory compliance and monitoring, but again, the ERG does not serve this purpose; rather, it is action-oriented for immediate incident response. Thus, the correct answer emphasizes the ERG's role as an on-the-scene guide for first responders in emergency situations.