ILO Convention n° 174 on the Prevention of Major Industrial Accidents – the purpose of this Convention is the prevention of major accidents involving hazardous substances and the limitation of the consequences of such accidents. It applies to major hazards installations, which are defined by the presence of quantities of hazardous substances that exceed a specific threshold. Ratifying states are allowed a large measure of discretion in identifying and designating the installations concerned, inasmuch as threshold quantities are to be prescribed in national laws and regulations.