What is the first step in responding to a hazardous materials incident?

The first step in responding to a hazardous materials incident is to size-up the situation. This involves assessing the scene to gather critical information about the nature of the incident, including identifying the substance involved, the extent of the spill or leak, any potential hazards, and the environment surrounding the incident. This comprehensive assessment is crucial for informing the subsequent actions to be taken, whether that be containment, evacuation, or alerting emergency services. Proper sizing-up allows responders to make informed decisions that prioritize safety and efficiency, ultimately leading to a more effective response to the hazardous materials incident.