Industrial gases are a group of gases that are specifically manufactured for use in a wide range of industries, which include oil and gas, petrochemicals, chemicals, power, mining, steelmaking, metals, environmental protection, medicine, pharmaceuticals, biotechnology, food, water, fertilizers, nuclear power, electronics and aerospace. Their production is a part of the wider chemical Industry (where industrial gases are often seen as ""speciality chemicals"").The principal gases provided are nitrogen, oxygen, carbon dioxide, argon, hydrogen, helium and acetylene; although a huge variety of gases and mixtures are available in gas cylinders.The industry producing these gases is known as the industrial gases industry, which is seen as also encompassing the supply of equipment and technology to produce and use the gases.Whilst most industrial gas is usually only sold to other industrial enterprises; retail sales of gas cylinders and associated equipment to tradesmen and the general public are available through gas local agents and typically includes products such as balloon helium , dispensing gases for beer kegs, welding gases and welding equipment, LPG and medical oxygen. Very small scale gas supply is not confined to just the industrial gas companies. A wide variety of hand-carried small gas containers, which may be called cylinders, bottles, cartridges, capsules or canisters are available to supply LPG, butane, propane, carbon dioxide or nitrous oxide. Examples are whippets, powerlets, campingaz and sodastream.