What type of breathing apparatus is commonly used by firefighters in Seattle?

Self-Contained Breathing Apparatus (SCBA) is the correct choice for the type of breathing apparatus commonly used by firefighters in Seattle. This equipment is crucial for providing breathable air in hazardous environments, such as smoke-filled buildings or areas with hazardous materials. SCBA units contain a tank of compressed air, which allows firefighters to operate effectively in situations where the air quality is compromised.

The SCBA is designed to ensure that firefighters can perform their duties safely while maintaining mobility and functionality. It typically includes a mask that covers the face and a regulator that allows the user to breathe from the air tank comfortably. Additionally, SCBAs are equipped with alarms to warn users about low air supply, which is critical for safety in emergency situations.

In contrast, other types of breathing apparatus mentioned may have specific applications but do not match the level of protection and self-sufficiency that SCBAs provide in firefighting operations. For example, open-circuit breathing apparatus are used in certain industrial environments, while continuous flow breathing apparatus is less common among firefighters due to their limitations in providing the necessary air supply in high-risk scenarios.