Propane Tanks Alternative ways to recycle Illegal in Garbage & Drains Hazardous Waste Compressed gas or propane cylinders greater than 5 gallons or 20 lbs will not be accepted at the landfill as household hazardous waste. You will need to look at alternative ways to recycle this item, shown below. Do Not Tamper With If you are waiting to dispose of a tank, store them outside and upright with their caps on tight. Write empty on the container, and do not try to remove the valve. Especially Hazardous if Not Empty A propane tank is still pressurized and can explode or start a fire if it’s not entirely empty. Propane can also be damaging to your health if touched or inhaled, so any tank that is not empty must be disposed of as hazardous waste. Use Up Completely Empty propane tanks are less likely to injure people, because the tank is not pressurized with propane gas. Alternative Ways to Recycle AmeriGas Offers Free Tank Disposal You can dispose of propane tanks by returning them to AmeriGas. Find an AmeriGas office. Fees may apply.