Things you shouldn’t leave in hot cars

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It is the British summer and, unusually, we are basking in sweltering temperatures. As much as people moan about the country falling apart over some sunshine, we are notoriously rubbish in extreme temperatures. With that in mind, it is worth looking at the dangers we might not normally think about. Here are some things you shouldn’t leave in hot cars.

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Water bottles

We should all be hydrating more on sunny days. However, if you have a plastic water bottle on the go, do not leave it in the car. The water can refract the sunlight like a magnifying glass, concentrating a hot beam on potentially flammable upholstery. This has caused car fires in the past, and all because someone absent-mindedly left a bottle in the car like they had probably done a hundred times before.

Here’s a video about the potential dangers of water bottles in hot cars:

Anything containing gas

Other items that can cause real damage in a car are those that contain gas. These include lighters and aerosol cans. The heat causes the gas to expand and can lead to explosions. Just like in this case:


Many of us keep pens in our cars. Even with notes apps on phones, it’s good to have a handy pen around to write down details in an emergency. However, heat can really affect them and when the heat is really intense, there is the chance that your pen could explode and leave you with an inky mess to clean up. That’s no fun for anyone.


You might not realise this, but medicine left in hot cars can lose its potency. This means that, if you rely on medication for a condition, you might not receive the full effect. In other cases, it can change the way is affects you, which could be an area of concern. When you leave your car, make sure you take your medication with you and keep it out of direct sunlight.

The obvious ones

Not mentioned yet, but they are the real obvious ones. Don’t leave your kids or pets in a hot car. The temperature can rise even when the car is in shade and you need to remember that it can get much hotter inside the car than the outside temperature too. If it’s a scorcher, the car will be like an oven and could have disastrous effects for anyone stuck inside.

Does alcohol hand sanitiser explode in cars?

Interestingly, although many viral internet posts suggest that hand sanitiser can explode at low temperatures, there is more to it. It is true that it cannot explode at lowish temperatures (think mid-20s), but it needs an external spark to do so. It will only explode on its own when heated to more than 300 degrees.

However, the warning above about direct sunlight through a clear liquid in a clear bottle stands. You are much better to take it out of the car with you.


Are there any other items you shouldn’t keep in hot cars? Let us know in the Comments

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