What resource should be consulted first to determine the size of a hazardous materials incident?

The Preincident Plan is a crucial resource for determining the size of a hazardous materials incident because it contains pre-established information about potential hazards, resources, and responses specific to facilities or areas. This document typically includes site evaluations, chemical inventories, and emergency procedures tailored to various scenarios.

Using the Preincident Plan allows responders to quickly assess the scale and scope of an incident based on known variables. It informs decision-making on resource allocation, potential evacuation zones, and how to coordinate with neighboring agencies or larger emergency response systems.

While other resources like the Unified Command System are important for managing incidents, they work best when the initial size and scope of the incident have been assessed. The Emergency Response Guidebook provides general guidance on managing hazardous materials incidents but does not specifically tailor the information to a specific location or scenario as the Preincident Plan does. The Hazardous Materials Handbook contains detailed information about various materials but lacks the specific situational context needed to assess an ongoing incident's size effectively.