What should firefighters do if they suspect their air supply is compromised?

When firefighters suspect that their air supply is compromised, the most appropriate action is to evacuate the area and seek fresh air. This is crucial for ensuring the safety of the firefighters and maintaining their ability to function effectively. A compromised air supply could indicate the presence of dangerous gases, smoke, or other hazardous conditions that could lead to suffocation or other serious health risks.

By moving to an area with fresh air, firefighters can prevent potential inhalation of toxic substances while also allowing themselves to assess the situation without the immediate threat of diminished oxygen levels. This act of prioritizing their safety enables them to make informed decisions on how to proceed with the firefighting efforts in a safe manner.

Other options like ignoring the situation or solely monitoring oxygen levels do not effectively address the immediate danger. Switching to a backup air supply, although a potential solution, might not provide enough time to effectively address the risk if conditions are severely compromised. Therefore, evacuating and seeking fresh air is the most sensible and life-saving course of action in such scenarios.