What does a flashing rapidly red light on the MMR indicate?

A rapidly flashing red light on the Mask Mounted Regulator (MMR) indicates a critical alert concerning the user's safety. Specifically, this signal is designed to inform the user that they are in a hazardous atmosphere and must leave immediately to avoid potential harm. The urgency of this warning is paramount, as it signifies that conditions may be deteriorating, and immediate action is required to ensure personal safety.

In the context of SCBA use, the MMR serves as an important feedback mechanism, helping users manage their environment while operating in potentially dangerous situations. Recognizing and responding to these alerts can be crucial in maintaining safety during firefighting or rescue operations.