Gas Cylinders are designed to be refilled and there are many companies offering this service, see the Yellow Pages under Bottled Gas & Equipment.
If you no longer require your cylinder it should be returned to the place of purchase.
Recycling the steel means less energy is needed to make a new cylinder, rather than making it from virgin material. Steel is also a valuable material which means that money can be made by recycling it.
Dangers Of Gas Cylinders:
Gas cylinders present a threat because:
Pressurised - violent release of contents
Flammable - such as butane or methane
Toxic - such as chlorine
Although gas cylinders are no longer classed as a hazardous shipping material, they still need to be treated carefully as residues of gas can still remain within the canister which could cause an explosion.
Gas canisters should not be disposed of by throwing them in with regular household trash, because they need special disposal facilities that take away the risk with recycling them.
If you find a damaged gas cylinder that may still contain gas, you should report it to your local authority because it may represent a environmental and safety hazard.
Gas cylinders are often colour coded for different gas types, however it is always best to look at the label to identify what gas is within the container.