Camping fuel is the most hazardous substance most outdoor enthusiasts store in their homes. A single 8 oz isobutane canister contains enough flammable gas to cause a serious fire if stored improperly. A gallon of white gas has the explosive potential of several sticks of dynamite if its vapors accumulate in a confined space and encounter an ignition source. The safety guidelines for fuel storage are not suggestions -- they are based on the material properties of pressurized gases and volatile liquids.
Isobutane-Propane Canister Storage
The EN417 threaded canisters used by Jetboil, MSR PocketRocket, Soto WindMaster, and similar stoves contain a mixture of isobutane (typically 70 to 80 percent), propane (20 to 25 percent), and sometimes a small amount of butane. The propane content maintains adequate vapor pressure for cold-weather performance.
Canister pressure and temperature relationship. At 20C (68F), a standard canister has an internal pressure of approximately 45 to 55 psi. At 50C (122F), pressure rises to approximately 130 to 150 psi. At 70C (158F), pressure exceeds 200 psi. The canister's pressure relief valve typically activates at pressures corresponding to roughly 80C to 100C internal temperature.
This means a canister stored in a vehicle on a summer day is at risk. Car interiors in direct sun with an outside temperature of 35C (95F) can reach 60C to 70C (140 to 158F) within 30 minutes. The canister's relief valve may vent gas to prevent rupture. If the vented gas encounters an ignition source (a cigarette, an electrical spark from a door lock actuator), the result is a fire or explosion.
The basic rules for canister storage:
- Store at temperatures below 50C (122F) at all times. This means never in a vehicle in warm weather, never in direct sunlight, never in an attic or shed that gets hot.
- Store away from ignition sources: water heaters, furnaces, clothes dryers, electrical panels, any appliance with a pilot light or spark ignition.
- Store in a well-ventilated area. If a canister leaks, the gas should dissipate outdoors, not accumulate in an enclosed space. A garage with a permanent ventilation opening is acceptable. A closet inside the house is not.
- Do not store canisters in your living space (bedroom, living room, kitchen cabinets near the stove). A detached garage or outdoor shed is ideal.
- Keep canisters out of reach of children and away from curious hands.
- Do not store partial canisters long-term. Use partially full canisters on your next trip rather than letting them sit for a year. The seals can degrade, leading to slow leaks that empty the canister into your storage space.
Shelf life of sealed canisters. An unopened, undamaged isobutane-propane canister has an effectively indefinite shelf life if stored properly. The gas mixture does not degrade or separate over time. The steel canister body can eventually rust if stored in a humid environment (a damp basement, an outdoor shed in a rainy climate). A rusty canister should be disposed of, not used, because the rust thins the steel wall and reduces its pressure-holding capacity. A canister that ruptures during stove attachment due to a weakened wall sprays liquid fuel that instantly vaporizes into an explosive mixture.
Disposing of old or damaged canisters. Do not throw camping fuel canisters in the trash. Most municipal household hazardous waste facilities accept them. REI stores in some locations have canister recycling programs. To safely empty a canister before disposal: use it on a stove outdoors until the flame dies. Puncture the empty canister with a canister puncturing tool (Jetboil makes one called the CrunchIt, about 5 USD; MSR and others make similar tools) to ensure it is depressurized. The punctured canister can then be recycled as scrap steel in most recycling programs.
Liquid Fuel Storage: White Gas, Kerosene, Petrol
Liquid camping fuels present different risks from canisters. The primary hazard is not pressure (these fuels are stored at atmospheric pressure in unpressurized bottles) but vapor accumulation. A single gallon of white gas spilled in a closed garage produces enough vapor that the air-fuel mixture can ignite explosively from the spark of a light switch being flipped.
Fuel bottles. MSR, Optimus, and Primus fuel bottles are made of aluminum or steel with a rubber gasket in the cap. The gasket prevents leakage but degrades over time. A fuel bottle stored for a year with fuel inside may develop a slow leak through a dried-out gasket. Check gaskets annually and replace them if cracked or flattened. Replacement gaskets cost about 2 USD and are sold by MSR and Optimus.
Storage containers. Store liquid fuel only in purpose-made fuel bottles or the original container it came in. Never use a water bottle, soda bottle, or any container not designed for flammable liquids. Fuel (especially white gas, which is chemically similar to naphtha) can dissolve many plastics. A fuel bottle labeled "MSR" or "Optimus" is made of HDPE or aluminum-specified for fuel storage. A generic plastic water bottle is not -- the fuel will dissolve the plastic over time and create a leak.
Vent location. The absolute non-negotiable rule: store liquid fuel in a space that is ventilated to the outdoors. A shed with a louvered vent, a garage with a permanent air gap, or an outdoor storage box designed for flammables. If fuel vapors can accumulate in an enclosed space, that space is a bomb waiting for a spark.