The gas cylinder, also known as a compressed gas cylinder or acetylene cylinder, is the container used for storage and dispensing of many industrial and laboratory gases. Cylinders are generally highly pressurized containers of metal, often with internal valves, and may be filled with flammable, non-flammable, or chemically reactive products. The high pressure, the weight of the cylinder and the hazard characteristics of the contents present multiple safety risks, and extreme caution should always be exercised when handling a gas cylinder.

The use of gas cylinders is heavily regulated by governments around the world, and different regions have their own requirements for handling, transporting and storing cylinders. Many of these requirements include a series of exterior markings that identify the product within the cylinder, and some even require additional testing.

Cylinders are available in two main types: refillable and non-refillable. Non-refillable cylinders are designed for single-use and should never be refilled or reused. Refillable cylinders are made of steel and aluminum, and are designed for repeated refilling and use. Both types of cylinders must be kept in good condition and free from damage, tampering or improper handling. Cylinders must be visually inspected prior to each use, and any signs of damage or wear should be reported to the gas vendor immediately.

Gas cylinders are usually highly pressurized, and must be reduced from their stored high pressure to a usable level by the use of a pressure regulator. The cylinders and the pressure-release devices should never be tampered with, and all caps must be securely fastened. The cylinders should be secured to prevent tipping, and may be attached to a bench or wall, placed in a cage, or secured with chains to a stand or crate. The cylinders should be stored in an area that is suitable for the type of gases, and they should be separated by compatible groups (flammables from oxidizers, etc.).

Whenever possible, all cylinders should be returned to the gas vendor when they are empty. This reduces the need for handling, recharging and reusing high-pressure cylinders, which increases safety and efficiency. The gas vendors should provide a tracking system that ensures the correct replacement is sent and that the return process is handled correctly.

Cylinders must be secured at all times to prevent them from falling or rolling, and they should be stored in a location that meets local and national regulations. Cylinders should be securely stored with chains or straps connected to the cylinder base, or placed in a crate that is mounted on a specially designed stand. The cylinders should be stored in a secure, non-tip location, and they should be separated by size where appropriate (flammable cylinders from non-flammables).

Cylinders that are damaged should be removed from service immediately, and should not be refilled or recapped. They should be returned to the cylinder vendor for proper inspection and repair, or returned to the manufacturer if they are not safe for reuse. The cylinders should be disposed of properly to avoid environmental contamination and hazardous waste disposal issues.