What type of incidents does the ERG primarily address?

The Emergency Response Guidebook (ERG) primarily addresses hazardous materials incidents, making this answer the most appropriate choice. The ERG serves as a vital reference for first responders to identify and manage incidents involving dangerous goods and hazardous substances. It provides guidelines on how to safely respond to various chemical spills, leaks, and other emergencies involving hazardous materials, ensuring that personnel are equipped with the necessary information to protect themselves and the public.

The focus on hazardous materials is crucial because these incidents pose unique risks that require specialized knowledge, appropriate safety measures, and specific procedures for containment and mitigation. The ERG includes an extensive list of chemicals along with safety data sheets, evacuation procedures, and information to assist in the assessment of risks associated with hazardous materials.

Other options such as fire incidents, natural disasters, and medical emergencies do not fall within the main scope of the ERG. While these situations may involve hazardous materials, the ERG specifically provides guidance tailored to chemical emergencies, making it a critical tool for managing those types of incidents effectively.