According to Safe Work Australia, a confined space is determined by the hazards associated with the specific situation—not just because work is performed in a small space. A confined space means an enclosed or partially enclosed space that: Is not designed or intended to be occupied by a person. Is at normal atmospheric pressure—or is designed or intended to be at normal atmospheric pressure—while a person is in the space. Is a risk to health and safety from: an atmosphere that doesn’t have a safe oxygen level contaminants like airborne gases, vapours and dusts that may cause injury from fire or explosion. Has harmful concentrations of any airborne contaminants. Is at risk of engulfment. Confined spaces are commonly found in vats, tanks, pits, pipes, ducts, flues, chimneys, silos, containers, pressure vessels, underground sewers, wet or dry wells, shafts, trenches, tunnels or other similar enclosed or partially enclosed structures, according to model WHS regulations. A space may become a confined one if work carried out in it could generate harmful concentrations of airborne contaminants.