This article is about a particular make of USA naval breathing set. For oxygen breathing sets in general, see rebreather.
An Oxygen Breathing Apparatus or OBA is a rebreather. It is used primarily in firefighting. Its oxygen is generated by chemicals contained in the green canister, which is inserted at the base of the breathing device. The canister uses potassium superoxide as both a CO2 scrubber and an O2 generator. A sodium chlorate candle in the base generates additional oxygen when first beginning use.
As of early 2001, the US Navy has been replacing the OBA for firefighting with the SCBA. The SCBA is more cost-effective than the OBA, and also does not produce hazardous waste, a problem with the chemical oxygen generation system.