What is the first step that responders should take in an emergency situation according to the ERG?

In an emergency situation, the first step that responders should take, as outlined by the Emergency Response Guidebook, is to identify the materials involved in the incident. This step is crucial because knowing the specific substances involved helps responders determine the appropriate safety protocols and response strategies. Different materials can present various hazards, including toxicity, flammability, and reactivity. By identifying these materials early in the response, responders can assess potential risks to themselves, other emergency personnel, and the public, and can take informed actions to mitigate those risks.

Understanding the nature of the substances involved allows responders to select the right protective equipment, establish safe zones, and inform subsequent response actions, such as containment, cleanup, or evacuation if necessary. This prioritization of material identification is vital in managing the scene effectively and safely.