What is the first step when encountering a casualty?

The first step when encountering a casualty is to assess the scene for safety. This step is crucial because it ensures that both the rescuer and the casualty are not in immediate danger from the environment or any potential hazards, such as traffic, fire, or unstable structures. By ensuring a safe environment, the rescuer can effectively provide care without putting themselves at risk of injury or worsening the situation.

Approaching the casualty without a safety assessment could lead to further complications if there are dangers present that the rescuer has not identified. Calling for professional help is important, but it usually comes after ensuring the scene is safe for intervention. Checking the casualty's vital signs is also a necessary action, but it occurs only after confirming the safety of the scene. Thus, assessing the scene for safety is the foundational step in effective self-aid and buddy care.