While the cylinder label is the primary means of identifying the properties of the gas in a cylinder, the colour coding of the cylinder itself provides a further guide.
Most important colours
| Poisonous and/or corrosive gases | Yellow |
| Combustible gases | Red |
| Oxidizing gases | Light blue |
| Inert gases | Light green |
Pure Gases
| Acetylene | Maroon |
| Oxygen | White |
| Argon | Dark green |
| Nitrogen | Black |
| Carbon dioxide | Grey |
| Helium | Brown |
| Hydrogen | Red |
| Nitrous oxide | Blue |
AGA cylinder colours
| Industrial gases | Black |
| Acetylene | Maroon |
| Food gases | Green |
| Specialty gases | Silver grey |
| Medical gases | White |
