Yes, pumping gas with your car's engine running is dangerous. While the odds of an actual fire are statistically low, the risk is real and preventable. The primary hazards are ignition sources from the engine compartment and the potential for a static electricity discharge. Modern vehicles and gas pumps have multiple safety features, but these are not foolproof against a running engine's heat, electrical sparks, or the volatile fuel vapors present during refueling.
The core danger lies in the fuel vapor concentration around the fuel filler neck. Gasoline is highly flammable in its vapor form. A running engine presents several potential ignition sources:
- Heat: Components like the exhaust manifold or catalytic converter can reach temperatures exceeding 1,000°F (538°C), easily enough to ignite gasoline vapors.
- Electrical Sparks: The engine's electrical system, including alternator and spark plugs, operates constantly and can produce sparks.
- Static Electricity: This is a common cause of gas station fires. While you can build up static charge by getting in and out of your car, a running engine's moving parts (like fan belts) can also generate a static charge.
Beyond the fire risk, a running engine increases the chance of a fuel system pressure issue. Some modern vehicles have complex evaporative emission control systems (EVAP). Refueling with the engine on can confuse the system's sensors, potentially triggering a check engine light or, in rare cases, causing damage. The safest and simplest practice is to always turn your engine off, avoid re-entering your vehicle during pumping, and touch a metal part of the car away from the filler neck to discharge any static electricity before handling the nozzle.
