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Accidentally Left the Car Running in the Garage For 2 Minutes (What Can Happen…)

Accidentally Left the Car Running in the Garage For 2 Minutes (What Can Happen…)

We’ve heard it time and again. That carbon monoxide (CO) is one of the most, if not the most, deadly gas out there. And yes, from the reports we’ve seen, it is. According to the Centers for Disease Control and Prevention (CDC), CO is responsible for more than 50,000 visits to the emergency room and even worse, 430 deaths in the United States every year.

CO emanates from the incomplete combustion of carbon-based fuels, such as gasoline, natural gas, propane, oil, coal, or wood. When these materials burn, they release CO gas. Vehicles or engines left running in an enclosed space, like a garage, can rapidly fill the area with CO gas. But can accidentally leaving your car running in the garage for 2 minutes be that dangerous?

Well, that’s what we’re here to discover. In this article, we’ll explore all there’s to know about CO gas, including how lethal it is, how long it takes for a typical car engine to produce lethal levels of CO, and so much more. I mean, there’s so much to learn here.

Read: Accidentally Left Gas Stove On For 20-30 mins Without Flame

What Happens When You Leave a Car Running in the Garage For 2 Minutes?

When you leave a car running in the garage for 2 minutes, what happens is that it will lead to carbon monoxide build-up. CO build-up can be so rapid that it can leave you in a deadly situation in just a few seconds. That’s why you should never leave a car running in the garage.

Before we proceed, it’s worth mentioning this; there’s nothing you can do to stop your car from producing CO gas. Even if you have the latest machine, it will still emit CO as long as the engine runs on fossil fuels.

That’s something that has happened since the time cars were invented. However, we’ve had significant modifications in the car engine design, fuel, and car exhaust systems, all to reduce the amount of CO produced.

But even with these efforts, car engines still produce significantly high amounts of CO. It’s so high that they can cause a lot of harm and even death. And in the case of an enclosed space like a garage, these high levels of CO can build up very quickly.

A study by the CDC reveals that it takes approximately 7 minutes for a typical 5HP gasoline engine to hit the Immediately Dangerous to Life and Health (IDLH) CO concentration of 1200 parts per million (PPM) when running in a 10000 cubic feet room. That means in just 7 minutes, the level of CO in the garage would be high enough to kill you.

And to reiterate, that’s just a 5-HP engine! An average car engine ranges between 100 and 200 HP! So you can only imagine how quickly a car engine would produce lethal levels of CO in just a few minutes. That’s why leaving a car running in the garage is horrific, even for just a few minutes.

Read: Ways to Keep Birds Out of Garage

Is It Dangerous To Leave Your Car Running in the Garage?

Yes, it’s dangerous to leave your car running in the garage, as it can cause carbon monoxide poisoning. If lucky enough, CO poisoning leaves you with mild headaches, dizziness, and nausea. However, more severe cases can cause brain damage and even death.

You see, carbon monoxide isn’t one of the gasses you can joke around with. It’s one “silent-killer” sort of gas. And by the way, it’s also commonly referred to as the “silent killer” gas.  That’s because it’s non-irritating and you can’t see, taste, or even smell it. So, your sharp sense of smell won’t come in handy in this case.

And when you inhale CO, it reduces the blood’s ability to carry oxygen. And as it starts to build up in your system, it first affects the areas that require more oxygen, and that includes your brain and heart.

When your brain doesn’t get enough oxygen, it will start to malfunction. You experience flu-like symptoms, such as headache, dizziness, and nausea. In extreme cases, it can cause seizures, brain damage, and even death.

And yes, it doesn’t only remain in the garage. CO can easily sneak into your house, especially if you have an attached garage. An Air infiltration and Ventilation Centre (AIVC) report suggests that 5-85% of CO in your garage can end up in your house, especially if your garage is next to it.

And as it diffuses into the house, it dilutes into lower concentrations. Even so, sometimes, the consequent concentration is high enough to trigger the indoor CO detectors in your house. That should show just how saturated your garage will be with CO if you leave your car running there.

How Long Can You Sit in the Garage With the Car Running?

You should avoid staying in the garage for long periods with the car running. The only time you should stay in your garage with your car engine running is when sliding it in or out. And of course, even during these times, you should take the necessary measures, such as leaving the door open to let in air.

Remember, you’re dealing with a subtle gas that can cause serious health problems. Sitting in the garage with a running engine is simply asking for trouble. So, the best thing you can do is to avoid staying in your garage with your car running.

Can You Die From Sitting in a Car in the Garage?

You can die from sitting in a car in the garage if the garage is not ventilated and the car is running. Carbon monoxide (CO) can easily sneak into your car, especially if there are holes in the car body or the tailgate is open. When that happens, the CO will start to build up in the car, which can be very dangerous.

As already stated earlier, CO is colorless, odorless, and tasteless. So, you might not even know that it’s there. That’s why it bears the nickname the “silent killer” at first. That means you can’t sit in your car and say you’ll act when you start feeling the symptoms. By then, it might be too late.

When dealing with CO, things can go south very quickly. It’s likely that you may even collapse even before you know that you’re in danger. For that reason, just to be on the safe side, you should avoid sitting in your car in the garage, even with the garage door open.

Perhaps you’ve heard people argue that carbon monoxide is lighter than air, so it’ll just rise and dissipate. Well, there’s some truth in the weight argument. CO has a molar mass of 28.01 g/mol, while air has 28.97g/mol. But as you can see, the difference is so insignificant that CO can evenly distribute itself within your indoor space.


Can You Warm Up the Car in the Garage?

Don’t even think of warming up the car in the garage. Cars produce more CO at startup than at any other time. Sometimes CO levels can rise to 80,000 PPM in the first minute, about 67X the NIOSH’s maximum level for human exposure (1,200 PPM).

If you’re planning on warming up a car, it’s likely because the engine is cold and needs some time to warm up. But that’s actually the worst time to be around a car, especially in an enclosed space like a garage.

That’s because when you start a car, the initial fuel mixture is high, and the catalytic converter – the tool responsible for reducing emissions – is cold and ineffective. That results in significant CO production of 80,000 PPM in the first minute. That’s according to The National Institute for Occupational Safety and Health (NIOSH).

However, as the car continues to run, the fuel mixture will gradually lean out, and the catalytic converter will warm up and become more effective. By the 15th minute, CO production may have decreased to as low as 300 PPM.

Of course, these are just averages. The actual numbers will vary depending on the car, fuel type, and engine temperature. But regardless, you should never warm up a vehicle in an enclosed space. I recommend that you do it outdoors where there’s plenty of ventilation.

Read: Stop Birds From Pooping on Car

Is It OK To Leave the Car Running in the Garage With the Door Open?

Leaving a running car in the garage is never OK, even when the door is open. A typical car engine’s CO emission is so high that even leaving the door open won’t help bring the concentration down to a safe level.

Cars are heavyweight CO producers. They produce so much that even a well-ventilated garage can’t disperse the fumes quickly enough. That’s why you should never succumb to the temptation of leaving your car running in the garage, even if it’s just for a few minutes.

Is It OK To Sleep in My Car With the Engine Running?

Again, the answer is no. You should never sleep in your car with the engine running, even if all car windows are closed. The CO fumes can still sneak into your car through the seemingly tiny gaps and holes and put you to sleep for good.

Sometimes we get so tired at work that when we finally make our way home, all we want is to take a short nap in the garage before we finally walk into the house. However, no matter how irresistible that sounds, never do it. It’s simply not worth the risk.

The air quality in your garage can easily get compromised, and you might not even realize it. And that’s not just because of CO from your car. A garage serves as a  storage space for all kinds of things – cleaning chemicals, paint cans, power tools, etc. All these can release harmful fumes that can mix with CO from your car and create a very dangerous situation.  

Final Verdict

Cars can, in seconds, produce enough CO to kill or put one in a hospital bed. That’s why it’s never advisable to leave your vehicle running in the garage, whether all the entryways are open or not. And unfortunately, there’s no way you can use a residential CO detector to know if the levels in your garage are at a safe level.

Since the garage is more susceptible to poor air quality and significant levels of CO, a typical detector in the garage would get damaged. So it’s better not to use one in the first place. The best way to protect yourself and your family is never to leave a running gasoline engine in the garage. Not even for a minute.