If a hazardous atmosphere alarm sounds, field personnel should first _________.

In the event of a hazardous atmosphere alarm, the immediate priority is to ensure the safety of all individuals in the area. Evacuating the area is essential because hazardous conditions may pose an immediate threat to life and health. When an alarm sounds, it indicates potentially dangerous atmospheric conditions that could lead to exposure to toxic gases, insufficient oxygen, or other hazardous substances. By evacuating promptly, personnel can minimize the risk of harm.

Addressing other actions, while calling 911, notifying control center personnel, and verifying the alarm are all important steps, they become secondary to the immediate need for personnel to move to safety. Prioritizing evacuation helps in ensuring that everyone is out of harm's way while further actions can be taken once the area is secure. This approach aligns with standard emergency response procedures, which emphasize protecting life first and foremost in hazardous situations.