What is the first step a firefighter must take before donning an SCBA?

Before donning a Self-Contained Breathing Apparatus (SCBA), it is essential for a firefighter to turn on the air cylinder. This action ensures that the air supply is activated and ready for use when needed. If the air cylinder is not turned on initially, the firefighter could be at serious risk if they find themselves in a hazardous environment and the SCBA is not functioning properly. This step guarantees that the firefighter has access to breathable air as soon as they put on the mask and are ready to enter the scene.

Checking the air pressure is an important step but typically comes after ensuring the air cylinder is on. Putting on the mask should occur only once the air supply is confirmed, and securing the tank is done in conjunction with preparing the SCBA for use. However, the fundamental first step is ensuring that the air supply is activated to avoid any potential hazards associated with a non-functional SCBA in an emergency.