Do not refill single-use propane cylinders. Attempting to refill a DOT-39 cylinder is extremely dangerous and can lead to serious injuries. The single-use cylinders are designed to be used one time only and can leak propane gas if refilled. Propane is an extremely flammable gas that must be kept away from fire or other ignition sources, as it can cause explosions and dangerous flash fires.
Always read and follow the manufacturer's instructions on the label for safe handling and storage.
Contact a qualified refiller to determine if a cylinder can be refilled properly.
Properly discard or recycle non-refillable cylinders when empty. Follow park rules on how to properly dispose of your garbage.
Check in at the Visitor Center or with the campground hosts to see if your park has propane canister recycling bins available.
Some parks require you to carry out your garbage and dispose of it offsite, especially if you have gone backcountry camping.
Contact a household hazardous waste program in your state for more details on the proper disposal of your propane cylinders if you take them home.
Make the switch to refillable canisters. Consider bringing a DOT-certified refillable 1 lb. propane canister. This way you don't have to worry about disposal and can help the park eliminate hazardous waste.