Contaminated or flammable atmosphere

Air in the work area that may hold harmful contaminants or flammable gases, vapours or dusts.

Also known as: Hazardous atmosphere, Flammable atmosphere, Contaminated air, Asphyxiation

How to control contaminated or flammable atmosphere

Do the work from outside the space, or remove contaminants by cleaning or purging before entry, where possible.
Isolate pipes and services that could let gases, vapours or liquids into the work area before anyone enters.
Ventilate with forced air, using intrinsically safe equipment where flammable gas may be present, and never ventilate with pure oxygen.
Test the atmosphere for oxygen, flammable gases and toxic contaminants with a calibrated gas detector before entry and during work.
Control entry with a permit, a standby person and a rescue plan that has been tested.
Provide supplied-air respiratory equipment where a safe atmosphere cannot be maintained.

Typical controls, most effective first. Your SWMS sets the controls for your own job and site.