The best way to store a used gas can is to ventilate it properly, keep it away from extreme temperatures and store it away from any open flame. The American Petroleum Institute recommends storing gas cans in a secure place away from the home or garage. The U.S. Occupational Safety & Health Administration instructs that gas storage cans should be stored away from very hot or cold temperatures and that they be kept away from exits and stairways.
Ensure that there is no leftover gas in the can, and tighten the cap securely before storing it. When storing a can with gas inside, do not overfill the can. Do not store gas cans near any sources of sparks, including static electricity, as sparks can ignite vapors and cause a fire. Keep the cans out of direct sunlight, and clean the outsides of cans to remove any fuel residue.
Place a fire extinguisher near stored gas cans as an additional safety precaution. If necessary, lock up cans to ensure that they are not within reach of children. Never smoke near stored gas cans. Regularly check them for damage or leaks, and soak up any spilled fuel using sawdust, paper or rags. Consult with local authorities for further gas can storage and disposal advice and regulations.
Researchers at Worcester Polytechnic Institute’s Department of Fire Protection have found that gas cans can explode under the right conditions if they contain excessive vapors or small amounts of gasoline. On rare occasions, vapors may come into contact with a spark, and flames can travel backward into the can and ignite the rest of the fumes inside. Gasoline that has been stored for long periods of time may become unstable and can create dangerously flammable conditions inside cans.