What phrase is used over the radio to initiate a primary search?

The phrase "Search and rescue" is used over the radio to initiate a primary search because it clearly communicates the intent of fire personnel to locate and rescue individuals who may be trapped or in danger within a structure. This phrase is essential in emergency situations as it conveys a sense of urgency and purpose to all responding units and establishes the focus of their immediate actions.

When responders hear "Search and rescue," they understand that their primary objective is to conduct a thorough search for victims while ensuring their own safety and the safety of others. This terminology is standardized within fire service operations, which helps maintain clarity and efficiency in communication during high-stress scenarios.

The other choices, while related to emergency operations, do not specifically denote the initiation of a primary search. Phrases like "Evacuate now" might indicate an urgent need for evacuation, "Ready for operations" suggests preparedness for action but is too vague, and "Command established" denotes the establishment of a command structure rather than signaling the commencement of a search effort. Each of these phrases serves a different purpose in incident command and operations but does not fulfill the role of calling for a primary search like "Search and rescue" does.