Three items it’s really dangerous to leave in your car on a hot day

Summer is still here. It’s very hot, and the extreme weather requires drivers to exercise extra caution and ensure you remove three common items from your car—because it’s dangerous to leave them there. The U.S. Centers for Disease Control and Prevention found that just one hour at an outside temperature of 26°C can cause the temperature inside the car to reach up to 60°C.

The first item you need to make sure is not in the car is medication.

Medications are something you should always remove from the car because many medications are heat-sensitive, including even acetaminophen (i.e., Tylenol, Dexamol, and Paramol), which should be kept at a maximum temperature of 25°C. If you leave them in the car, the heat can damage the medications, making them ineffective, and in some cases, even toxic. Nasal sprays or any medical substance in plastic containers can also be destroyed.

Some medications lose their effectiveness in heat due to the breakdown of their molecules or changes in their structure, and this condition can be life-threatening for some people taking critical medications whose condition could deteriorate quickly, such as diabetics and heart patients. Even a slight change in the medication dose can be catastrophic. Therefore, if you accidentally leave medications in a hot car, it’s best not to touch them and consult a doctor for a new prescription.

Of course, it’s very important to have a bottle of cold water in the scorching car to cool down, but it’s even more important not to leave the bottles in the car when you leave. Dehydration can be dangerous and affect driving, but always remember to remove disposable plastic bottles when done.

The heat inside the car can cause chemicals like a compound called polyethylene terephthalate (PET) in the plastic to leach into the water, and while the full health effects are not fully known, according to Food Safety News, it can affect the taste and color of the water.

But there is an even greater danger in leaving a bottle of water in the car—a bottle heated by the sun’s rays can be deadly and even cause a fire in the car. Don’t believe it? In a training video released by American fire services, you can see exactly how this can happen. As part of an experiment, experts left a water bottle on a leather seat or by the steering wheel in the intense heat, causing it to reach up to 100°C.

The bottle was so hot that it caused two holes in the leather seat. Fortunately, most manufacturers use fire-resistant materials, but if you leave the bottle next to materials like paper, clothes, or just trash in the car, they can cause a fire. For this to happen, the bottle must absorb a strong sunbeam at the right angle to reach optimal temperature, but don’t take risks—if you decide to leave a water bottle in the scorching car, it’s better to leave it in the glove compartment or a closed compartment, or choose a personal bottle made of non-transparent material that you fill yourself.

@allisonturquoise THIS is why you don't leave sunscreen in a hot car #sunscreen #spf #suncare #skincaretips #fyp ♬ original sound - Allison Turquoise

Like water, sunscreen is an essential item to take with you during a heatwave, but it’s important not to leave it in your car because it can overheat and lose its effectiveness—similar to medications. The heat can also cause the bottle to expand and build up pressure inside, which could make it burst—and no one wants to clean up greasy sunscreen residue from their car upholstery in the peak of summer heat.

Dermatologist Dr. Joseph Chao warns not just about the mess. “You should never leave sunscreen bottles in cars,” he says, explaining that sunscreens, especially chemical sunscreens with active ingredients like avobenzone and oxybenzone, can degrade when exposed to high temperatures in a car, which “leads to inadequate protection from harmful sun rays and subsequently sunburns, which pose a risk of developing skin cancer.”