No, you should never refuel a car with the engine running. It is a significant safety hazard. While the probability of an incident might seem low, the potential consequences are severe, including fire or explosion. The primary risk is from static electricity or a stray spark from the electrical system igniting gasoline vapors, which are highly flammable and present around the fuel filler neck. Modern vehicles have multiple safety systems, but intentionally creating a dangerous scenario is never worth the minimal convenience.
The primary dangers are:
- Ignition Source: The running engine, its electrical components, and the exhaust system are all potential sources of ignition. A single spark is all that's needed.
- Static Electricity: You can build up a static charge by getting in and out of your vehicle. A discharge when you touch the nozzle is a common cause of fueling fires, and a running engine increases the overall risk.
- Fuel System Sensors: Modern cars have sophisticated evaporative emission control systems (EVAP). Refueling with the engine on can confuse these sensors, potentially triggering a check engine light and storing fault codes because the system detects an unexpected pressure change.
While the odds are in your favor, the stakes are incredibly high. The safety procedure is simple: turn the engine off, and if you need to, get back in the car during fueling (e.g., in cold weather), be sure to touch a metal part of the car away from the filler neck to discharge any static electricity before handling the nozzle again.
| Hazard | Risk Factor | Supporting Data / Authority |
|---|
| Static Electricity Ignition | High | The Petroleum Equipment Institute cites static discharge as a frequent cause of fueling fires. |
| Vapor Ignition from Engine | Moderate to High | National Fire Protection Association (NFPA) code 30A prohibits refueling with engines running. |
| EVAP System Damage | Low to Moderate | Can trigger check engine lights; repair costs can range from $200-$500 for sensor replacement. |
| Legal Violation | High (at stations) | Explicitly forbidden by posted signage at virtually all gas stations in the US; can result in fines. |
| Potential for Catastrophic Outcome | Extreme | A gasoline fire can lead to total vehicle loss, severe injury, or fatality. |
