Fuel is found in vehicle tanks, buried station tanks, farm and home heating-oil tanks, propane cylinders and stocks of kerosene or spirits, and each carries a different hazard: gasoline vapour ignites easily, diesel and heating oil ignite far less readily, and propane is heavier than air and pools along the floor. Start with vehicle tanks and above-ground diesel tanks, because a buried station tank cannot be reached without a long-hose pump and close exposure to its vapour. Treat every tank as an unknown fuel until you have looked at it and smelled it.
Part of Fuel Siphoning & Storage
Fuel sits in vehicle tanks, buried and above-ground tanks, propane cylinders and shop stock, and each form has its own ignition behaviour and its own way of being reached. Knowing the fuel and the container comes before choosing the method.
Most Fuel Sits In Places You Can Reach Without Special Equipment
Every parked vehicle is a small tank. Passenger cars hold 40-70 litres, pickup trucks 80-135 litres and semi trucks 300-600 litres, according to the parent article. Those are capacities, not contents: an abandoned vehicle is rarely full, and a dashboard gauge only works while the battery still has charge. Plan on finding a fraction of the figure.
Beyond vehicles, the larger stores are fixed tanks: underground tanks at filling stations, above-ground diesel tanks on farms, oil tanks beside homes with oil furnaces, and the day tanks of standby generators at hospitals and commercial buildings. Propane lives in barbecue cylinders, forklift cylinders and large residential tanks. Kerosene, denatured alcohol and high-proof spirits are on hardware-store and liquor-store shelves. The details are in Passenger Vehicles & Trucks, Fixed Tanks & Depots and Alternative Fuel Sources.
Identify The Fuel Before You Touch It
Each fuel behaves differently once it leaves the tank, so identify it first.
- Gasoline: sharp, sweet smell, thin and clear to pale amber. The vapour is the danger, and it is heavier than air.
- Diesel and heating oil: oily smell, slightly slippery between the fingers, often straw-coloured. Farm diesel is often dyed red; the parent article notes that apart from the dye it is the same as road diesel.
- Kerosene: a lighter oil smell than diesel, thin and clear.
- Propane: a gas stored as a liquid under pressure. Leaks pool low and are treated at Propane, Kerosene & Other Fuels.
A smell test is for identification only. Do not sniff deeply at an open tank, because gasoline vapour is harmful to breathe and the point of the test is to identify, not to inhale. If you cannot tell what a fuel is, do not put it in an engine and do not store it in a sealed container with a labelled fuel you already know.
Priorities: Safest Reachable First
- Above-ground diesel and heating-oil tanks. Diesel and heating oil are harder to ignite than gasoline, and the tank is in the open air.
- Vehicle tanks, gasoline or diesel, taken one at a time outdoors with a pump, following Siphoning Techniques.
- Propane cylinders, moved upright and sealed, never opened.
- Buried station tanks last. They hold the most fuel and a vapour-filled space above it, and they need a long hose and a hand pump.
Common Mistakes
- Assuming a full gauge means a full tank. Gauges are electrical and fail with the battery; check by sight at the filler instead.
- Taking the largest source first. The biggest tank is usually the most dangerous one to open. A small, safe source taken calmly beats a large one taken badly.
- Mixing unknown fuels in one container. You lose the ability to say what the mixture is, and a fuel in the wrong engine causes damage that cannot be repaired without parts.
Safety
Gasoline vapour is the hazard, not the liquid
Gasoline gives off vapour that is heavier than air, collects in low spaces such as pits, trenches and the footwell of a vehicle, and ignites from a spark, a hot surface or static electricity across a wide range of concentrations. Open every tank outdoors, with no flame, no smoking and no running engine nearby. Never use a flame to check whether a tank or pit contains vapour; the only safe assumption is that it does. Read Fire & Vapor Safety before opening anything.
What’s Next
- Learn next: Siphoning Techniques — how to move fuel without breathing it or igniting it
- Combine with: Storage & Safety — where the fuel goes once you have it