Oxygen (O2) constitutes approximately 21% of the air, has a gaseous specific gravity of 1.1, and has a boiling point of -297.3°F (-183°C). Oxygen is produced by air separation processes that use either cryogenic liquefaction and distillation or vacuum swing adsorption (VSA) separation. Oxygen can be stored and shipped as either a gas or a cryogenic liquid.

The principal uses of oxygen stem from its strong oxidising and life-sustaining properties. It is used in medicine for therapeutic purposes and in the metals industry for steelmaking and metal-cutting applications. In the chemical and petroleum industries, oxygen is used in the production of a wide variety of fuels and chemicals. In the pulp and paper industry, oxygen is used for a variety of applications, including pulp bleaching, black liquor oxidation, and lime kiln enrichment. In the glass industry, oxygen/fuel combustion is used to reduce particulate and NOx emissions in melting operations. Oxygen is also used for gasification applications for producing synethesis gas to make chemicals, fuels, electricity, hydrogen or steam.