Lorraine Explains: Don't leave these items in a hot car

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As temperatures continue to set records, it’s time to revisit those things you might routinely leave in your car, and it’s time to make some changes. 

Everyone has come back to a hot car, but even with the A/C cranked to bring the temperature back to a comfortable level, that doesn’t remove the damage that heat has delivered to the contents of your car. Canada Safety Council warns that on a day with a temperature of 35 degrees Celsius (95°F), in just 20 minutes that can reach 50 degrees Celsius (122°F) inside the car. In 40 minutes, the inside temp rockets to 65.5 degrees Celsius (150°F). I put myself in that position back in July of 2018. It was horrible, as the video shows. 

Hot car stories are usually associated with the death and injury of children and pets left behind. This column isn’t about that, because surely we know better than to leave vulnerable beings in a locked car, right? If someone or something can’t safely get out of a car, you can’t leave them in it. Auto manufacturers are working to address safety systems to avoid tragedy, though the U.S. death toll currently sits at 20 for this year. Tesla created something called Dog Mode, so don’t go breaking windows if you see an unstressed pup; it’s likely cooler than you are.

This chart from the National Weather Service shows that even on breezy, cooler days, the inside of your vehicle can become deadly. That link also shows how useless cracking a window is. Even if you prop open your oven door a few inches, it could never combat the inside temperature. Same in a car. 

Here’s what (else) you shouldn’t leave in your hot car

Instead, it’s instructive to think about the inanimate objects that might be taking a beating in that heat. The water bottles, the laptops, the phones and more.

Don’t leave a single-use plastic bottle in a hot car

You’ve had a sealed water bottle riding around in your car for two weeks. Is it still safe to drink? Concerns arise not from the water, but from the container it is in. Most single-use plastic bottles contain polyethylene terephthalate (PET), which can “release various kinds of chemicals, including phenols like bisphenol A or BPA, and phthalates,” reports the New York Times. These chemicals can mess with your natural hormones, but the amounts used in food packaging has been deemed safe. You can ignore social media campaigns that have claimed the bottles could cause cancer. 

A more compelling argument against heating up your water bottles, however, is the issue of microplastics. You’ve seen the headlines that these forever plastics are being found in the most remote places on earth, like Everest, and deep in human brains and bones. Before food regulators change their tune on the safety of microplastics, you’re safer switching to metal or glass containers for your water bottles, or at the very least, not reusing single use plastics. 

Water bottles that have been opened (sipped from and recapped) are sketchier. Researchers found that bacteria, mold and yeast start forming in the left behind water at room temperature; exposed to the extreme heat of something like a car in summer means lots of nasty things besides microplastics and PET. While your little ones might be the most obvious backwashers, every contact with an open bottle leaves behind material for bacteria to form. All the more reason to move from plastic, or at least dispose of opened bottles instead of tucking them away for later.

Don’t leave electronics in a hot car

It’s highly unlikely your laptop or cellphone will burst into flames, but exposure to extreme temperatures will definitely take a toll on your battery. Both high and low temperatures can degrade your battery, cause cosmetic damage like warped screens or keyboards, data loss and component failure. Don’t underestimate how fast a car can heat up, and keep your laptop in a protective sleeve. I leave an insulated cooler bag in the car to protect any electronics that might need to stay behind; put them under a seat or other low spot in your vehicle. Remember: outside pleasant temperatures will steadily rise in a car parked in the daytime. 

Don’t leave medications in a hot car

Medications and sunscreen also fare poorly in extreme heat. While the most likely outcome is that they will lose effectiveness, you can’t tell visually if this has happened. Your glove box is one of the worst (though popular) places to store both. Particularly heat-sensitive are things like insulin, EpiPens, antibiotics, inhalers, diuretics and nitroglycerin. If you must leave them behind, make sure they’re in an insulated container.

Don’t leave food in a hot car

Groceries are expensive, and shouldn’t be left in a car while the internal temperature soars. From Consumer Reports, “The Department of Agriculture recommends that meat never be left unrefrigerated for longer than 2 hours—but that gets cut to just an hour when the temperature reaches 90° F (32° C). And bacteria continue to thrive until temperatures reach about 140° F (60 °C), according to the USDA.” Germs can grow as heat does, which can lead to food poisoning. Use insulated bags or ,if you have space, a cooler, for safety. 

If you’re lucky, you can find some shade to park beneath to keep your car cooler. Sun screens behind the windshield won’t do much to lower inside temperatures, but will help cut the UV rays that can fade and crack dashboards. As we get hotter days, and more hotter days, consider those things you’re leaving behind in your vehicle as you walk away. Insulate them or take them with you — sometimes the damage won’t be apparent.

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