What Happens If You Leave Hand Sanitizer In A Hot Car?

One of the ripple effects of the COVID-19 pandemic is that hand sanitizer has become ubiquitous. Most Americans now make sure to keep a bottle or two handy in their purse or jacket pockets, on their kitchen countertops, and of course, in their cars. While reports on social media have claimed that hand sanitizer left in a hot car is at risk of exploding, experts say you need not worry (via WebMD). 

While the high level of alcohol in these products makes them flammable, your car would need to heat up to about 700 degrees Fahrenheit in order for them to burn up or explode. No car gets this hot, even in the hottest regions of the United States in the dog days of summer. However, the U.S. Food & Drug Administration (FDA) advises that hand sanitizer should be kept away from open flames and should be rubbed into hands until they feel completely dry before partaking in activities involving heat, static electricity, sparks, and fire.

Will heat decrease the effectiveness of hand sanitizer?

While hand sanitizer will not explode if left in a hot car, it may become less effective. That's because long-term exposure to sunlight and heat can break down the alcohol in the sanitizer and cause it to evaporate. This causes the percentage of alcohol content to decrease, meaning it may not kill as many germs when you use it on your hands.

Still, keeping a bottle of hand sanitizer in your car can be a beneficial way to ward off coronavirus and other disease-causing pathogens when soap and water aren't available. But make sure to store the bottle out of direct sunlight, like in the glove compartment or side pocket of the door, and keep the cap tightly secured. Also, be aware that it may lose effectiveness over time, so make sure to replace the bottle frequently. According to Insider, a good rule of thumb is if the solution thickens and takes increasingly longer to dry when rubbed into your hands, it's time to replace it.