What is self-contained breathing apparatus (SCBA) used for?

Self-contained breathing apparatus (SCBA) is designed primarily to provide breathable air in environments that are oxygen-deficient or contain hazardous substances. In firefighting scenarios, smoke, chemicals, and other airborne pollutants can significantly reduce air quality, making it unsafe for firefighters to breathe without protection. The SCBA ensures that firefighters can operate in these dangerous conditions by supplying them with a safe source of air, which is crucial for their safety and ability to perform their duties effectively.

While cooling and signaling devices play important roles in firefighting, they do not pertain to the primary function of SCBA. Furthermore, while SCBA does provide some thermal protection, its primary purpose is centered on supplying breathable air rather than specifically addressing heat stress or temperature regulation during firefighting operations. This is why the correct answer emphasizes the importance of breathable air supply in hazardous conditions where firefighters need to ensure their safety while effectively combating fires.