This Sub-class includes the manufacture of industrial gases. Units in this Sub-class are primarily engaged in the manufacture of liquefied or compressed inorganic industrial or medical gases: elemental gases, liquid or compressed air, refrigerant gases, mixed industrial gases, inert gases such as carbon dioxide and/or isolating gases.
•extraction of natural gas such as methane, ethane, butane or propane, see 09001 •manufacture of fuel gases such as ethane, butane or propane in a petroleum refinery, see 1920