Carbon dioxide (CO2) is a liquefied, colourless gas that can asphyxiate in high concentrations. There are many different sources of CO2. It can be obtained from natural CO2 springs, limestone kilns, fermentation processes and gas streams from chemical and petrochemical plants. It can also be captured from the gas streams emitted by power plants.

Carbon dioxide has many well-known applications in the food and beverages industry – from carbonating drinks and conserving wine to modifying atmospheres for packaged foods. Dry ice – or solid CO2 – is commonly used for storage and transportation of temperature sensitive products such as frozen/chilled foods or medical/ pharmaceutical materials. Dry ice is used as a process coolant in food, chemicals, research and pharmaceutical industries and is also an extremely effective and environmentally sound cleaning agent. In agriculture, CO2 can be used to enhance growth in greenhouses and as a feedstock for algae that produce bio-oil (green crude).