Which of the following best describes a non-fire emergency?

A non-fire emergency is best characterized by incidents that involve significant risks to health or safety but do not involve a fire hazard. Option B describes a biological, chemical, or nuclear incident, which can pose serious threats to public health and safety and require immediate response and management. Such emergencies often necessitate specialized knowledge and protocols to mitigate their impact, which goes beyond the scope of fire-related incidents.

In contrast, incidents involving only fire hazards would fall under a fire emergency rather than a non-fire emergency. Minor disturbances in the building may not constitute a true emergency, as they could be resolved without immediate intervention. Lastly, an event that does not require immediate action suggests a lower level of urgency that typically does not align with the nature of non-fire emergencies, which often demand prompt and decisive action to ensure safety. Thus, option B is the most fitting description of a non-fire emergency.