A major accident facility is also known as a Major Hazard Installation. The definition of a major accident facility may vary country to country.
According to the International Labor Organization convention, C174 Prevention of Major Industrial Accidents Convention 1993, a major hazard installation means one which produces, processes, handles, uses, disposes of or stores, either permanently or temporarily, one or more hazardous substances or categories of substances in quantities which exceed the threshold quantity. Major accident facilities include, for example, PSM sites in United States or Seveso sites in Europe.