Asphyxiation due to oxygen depletion atmospheres

Abstract

Asphyxiation due to the creation of an oxygen depletion atmosphere (ODA) is by far the biggest cause of fatalities when working with cryogenic liquids. Each year, an average of 20 deaths occur in Europe involving people entering an ODA and between 1992 and 2002 in the USA, 85 nitrogen asphyxiation incidents were recorded, in which 80 people were killed. The likely causes of an ODA are confined spaces and poor ventilation, combined with the processing or storage of cryogenic liquids. Prevention can be made by providing well ventilated work areas, supported by the installation of oxygen monitors and alarms. A formal risk assessment document is part of the critical safety provision for personnel working in cryogenic areas. It stipulates how the prevention of an asphyxiation hazard is managed through the introduction of robust control measures and should include oxygen depletion calculations.