BA (short for Breathing Apparatus) is what is worn by firefighters when they enter an area with dangerous breathing conditions (most commonly a burning building filled with smoke) and they use them to be able to breath easily while performing the emergency or rescue.

A firefighters breathing apparatus needs to be heat and flame resistance. When a firefighter uses BA, they tend to be connected with a tally to a BA Board as this tells how much oxygen is left in the tank this feature is seen from Series 9 onward but was used briefly in Norman's Pitfall & Rich and Famous.