When at a fixed facility chemical plant, what information does first arriving personnel relay to dispatch during a leak or spill?

The correct choice focuses on critical information that first arriving personnel need to relay to dispatch during a leak or spill at a chemical plant. Sharing the UN (United Nations) or NA (North American) number provides a standardized way to identify hazardous materials. This can quickly inform emergency response teams about the specific properties and risks associated with the chemical involved.

The chemical name is also vital for understanding what substance is being dealt with, which influences the response strategy, potential risks, and necessary protective measures. Knowing both the UN/NA number and the chemical name allows dispatch and responding units to cross-reference information and prepare accordingly, ensuring that all responders are aware of the specific hazards they may face.

While names of plant staff on scene may be beneficial for coordination and communication, the immediate priority in a hazardous materials situation is ensuring that emergency services are aware of the specific chemicals involved, which is why the combination of UN/NA number and chemical name is essential. The other options do not adequately cover the most critical aspects necessary for initial response and safety assessment in a hazardous situation.