Can You Pump Gas With the Engine Running?

I’ve covered plenty of gas station-related topics on this page, from pumping tires to cleaning up gasoline spills. More importantly, I went over lots of safety tips and tricks that will keep both the drivers and their cars safe. Yet, people still ask me, almost on a daily basis, what my opinion is on pumping gas into the car while it’s still running. And those questions vary greatly — is it illegal to do that, is it safe, is it unsafe, can it kill us, can we protect ourselves, what are the fines, etc.

Can you pump gas with the engine running.

And from what I understand, I am far from alone when it comes to trying to find the proper answer to these questions. Shockingly, this very topic was hotly debated on, of all places, The Washington Post. But then again, there’s a reason why so many people want to know how to approach this issue. After all, pumping gas with the car running might actually be a matter of life and death.

The Dangers of Pumping Gas With the Car Running

Combustion

Gasoline is a flammable substance, and more importantly, one that catches fire incredibly quickly. Since most cars still run on gasoline, they are quite likely to get engulfed in flames if you don’t know what you’re doing.

In order for the fire to happen, you need three basic elements. The first is, obviously, the gasoline. Next, you’ll need an oxidizer, i.e., the oxygen in the air around the car. Finally, you’ll need a source of heat or ignition, so let’s cover those quickly.

Static Electricity

When you enter or exit the vehicle, you can build up static electricity. A single spark will be enough to ignite the gasoline. However, there’s a simple way to prevent that from happening. All you have to do is touch something made of metal when you’re leaving the car, such as the car door itself.

Some people advise against using cellphones because they can also create some levels of static electricity. However, this seems to be a myth, as there are no major recorded cases of cars catching fire due to the use of wireless phones.

Faulty Spark Plugs

Both spark plugs and spark plug leads have an important role to play within the engine. They are responsible for igniting the petrol/air mixture that makes a car run.

Usually, a spark plug has good insulation. After all, a single one can produce thousands of volts of electricity. So, if the insulation around the plugs were to break down, that electricity could potentially ignite my car. However, that’s not likely to happen, since cars with bad spark plugs have a hard time starting as is. Nevertheless, I’d highly advise replacing your spark plugs as soon as you notice any issues, just to be on the safe side.

Catalytic Converter

A catalytic converter is responsible for cleaning the exhaust of the engine. Because of what it does (and where it’s located), this part can get really hot really fast. In fact, the new models can handle temperatures of up to 900℃.

With that in mind, the heat from the catalytic converter can definitely be a source of ignition for our “car fire.” However, catalytic converters, especially high-quality ones,  tend to cool down quickly, so the danger is generally minimal.

Other Potential Sources of Heat and Sparks

By far the most frequent source of heat that can ignite gasoline at the station comes from smokers. That might not sound like a nice statement if you are one yourself, but I state it for good reason.

Most gas stations have warning signs that explicitly forbid smoking while refilling our car. And while most smokers obey this rule, there are those who act carelessly and discard cigarette buds at the station. Even if it were put out, the slightest ember could cause combustion.

Alternatively, smoking in a windy area can cause some hot cigarette ashes to float away. If any of the wandering hot particles end up close to the fuel tank, you can expect the car to burst into flames.

There are a few other potential spark sources in our car. For instance, loose battery terminals, faulty relays, and poorly installed electrical parts can all cause sparking to happen. Of course, the chances of these events causing fires are pretty low when we compare them to cigarette embers and static electricity.

Gas Poisoning

If my car is running when I’m pumping gas into it, lots of harmful vapors can escape into the air. Typically, cars have something called a vapor recovery system that keeps these harmful gases from reaching the atmosphere.

The dangers of harmful vapors are well-known; they contaminate the air we breathe and congest it. Moreover, they increase the global warming index and damage our ozone layer. That’s why it’s important to get rid of any lingering gas fumes and nasty smells, even when the car sits neatly in your driveway. I’ve covered this topic before, so feel free to give it a read right here:

Losing Money

Losing money isn’t strictly a life-and-death situation when it comes to this topic. However, I feel that I should cover it anyway; after all, there’s nothing better than staying safe and saving money by doing it.

Earlier, I mentioned vapor recovery systems. What I left out is that, by filling up your tank and keeping the engine running, you could actually damage this system. Of course, a mechanic would manage to repair it, but it would cost you quite a bit. In fact, it could cost you as much as $1,500.

Is It Illegal to Pump Gas With the Engine On?

The short answer is yes. The US law specifically states that you can’t leave your engine on while refueling. There are similar laws in the UK and in most of the other countries around the world.

So, why do some people still do it? Well, it depends on the context. For example, people in the United Arab Emirates constantly refuel with the engine running, despite it being illegal. The reason they keep doing it is the unbearable heat; as they’re refueling, they keep the air conditioning switched on so that the inside of the car doesn’t feel like a furnace.

The Bottom Line

So, what would be the final answer to the question of pumping gas into a still-running car? Well, it’s mixed. On the one hand, there is definitely a real danger in doing so because of the static electricity and the gas vapors. On the other hand, most new cars actually have built-in measures that prevent situations like these from happening.

Of course, pumping gas with the car running is just one of many things you should avoid doing at a gas station. If you’d like to add something to this conversation, feel free to do so in the comments below.

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