A self-contained self-rescue device, SCSR, self-contained self-rescuer, or air pack is a type of closed-circuit SCBA[1] with a portable oxygen source for providing breathable air when the surrounding atmosphere lacks oxygen or is contaminated with toxic gases, e.g. carbon monoxide.

Self-rescuers are intended for use in environments such as coal mines where there is a risk of fire or explosion, and in a location where no external rescue may be available for some time – the wearer must make their own way to safety, or to some pre-equipped underground refuge.

The main hazard here is from large quantities of carbon monoxide or whitedamp, often produced by an explosion of firedamp.

They are designed to have a long service life of around 10 years (longer for shelf storage) and to be worn every day by each miner.

To keep the catalyst functioning, the respirator has pre-filters of a dust filter and a moisture trap, as either contaminant would reduce its effectiveness.

A drawback to these respirators is that they rely on atmospheric oxygen in order for the catalyst to oxidise the carbon monoxide.

They are also used by people working with machinery on the surface of a mine or pit, in case they become covered by such materials as coal or sand.