Fire Dept's Warning Sparks Question: Is It OK To Leave Hand Sanitizer In Your Car?

As warmer months are on the horizon and the coronavirus pandemic carries on, a fire department in Wisconsin issued a safety reminder about leaving hand sanitizer in your car on hot days that went viral. While the Facebook post, which included an image of a badly burned car door, has since been deleted, you may be wondering whether or not it's safe to leave hand sanitizer in your car or if you should bring it inside with you.

Earlier this week, the Western Lakes Fire District in Oconomowoc, Wisconsin shared a Facebook post warning about the dangers of leaving plastic bottles of alcohol-based hand sanitizer in your car on a hot, sunny day. "Keeping it in your car during hot weather, exposing it to sun causing magnification of light through the bottle — and particularly being next to open flame while smoking in vehicles or grilling while enjoying this weekend — can lead to disaster," the now-deleted post read.

The photo from the post was originally taken in Brazil "after hand sanitizer contacted an open flame," a fire official from the Western Lakes Fire District told WFLA8. And although they did not respond to that fire, the official told WFLA8 that the fire departed wanted to warn people that hand sanitizer can be dangerous if it comes in contact with an open flame, specifically from cigarettes or from grills.

Hand sanitizer is, indeed, a flammable substance due to the alcohol in the product, according to the U.S. Centers for Disease Control and Prevention (CDC). Amid the pandemic, the CDC has recommended using hand sanitizer with at least 60% alcohol if soap and water are not readily available.

But how concerned should you be if you leave your bottle of Purell in the glove compartment?

Gel-based hand sanitizer would have to reach up to 363 degrees Celsius, which translates to around 685 degrees Fahrenheit, in order for the alcohol in the product to spontaneously combust in your car without an open flame, according to Brazilian news website, Estadão. Reinaldo Bazito, Professor of Chemistry Institute at the University of São Paulo, told the news outlet that "it's OK to leave small bottles in the car, as long as they are tightly closed and away from direct sunlight."

"Now, leaving a 500 mL or 1,000 mL bottle on the car's dashboard in direct sunlight is not a good idea!" he told the news outlet. "But still, it doesn't catch fire alone."

Vapors generated from the flash point of hand sanitizer — or temperature at which the liquid gives off enough vapor to ignite in air — would need an ignition source to catch fire in your car, according to the National Fire Protection Association. "For it to spontaneously combust with no other external ignition source other than self-heating alone, you'd have to reach over 700 degrees Fahrenheit!" the National Fire Protection Association confirmed in a YouTube comment from someone concerned about leaving hand sanitizer in the car's glove box.

Still, Florida Gulf Coast University Associate Professor Dr. Greg Boyce, who works in the department of chemistry and physics, told ABC 7 that people should not indefinitely leave bottles of hand sanitizer in their car because heat can potentially impact the effectiveness of hand sanitizer. And as temperatures continue to rise this summer, your car might not be the best place to store it. "So over a longer period of time at higher temperatures, you lose some efficacy in hand sanitizer because the active ingredient evaporates," Boyce told ABC7. "You want it above 60%, so if it stayed out for quite a while you would rather not use it."

The World Health Organization states that all alcohol-based products are potentially flammable and should be stored away from high temperature and flames. When you're not using your hand sanitizer, you should store it in a dry, cool, and well-ventilated place out of the reach of children, the American Cleaning Institute recommends.

After the Western Lakes Fire District Facebook post went viral, the fire department took to Facebook to clarify that the photo did not belong to them and their "message was intended to center on preventing fire or injury from the use of hand sanitizer."

"The open flame comment was to remind people that when hand sanitizer is wet on any surface, it will ignite when exposed to flame," the fire department wrote in a follow-up post on Thursday. "With the recent utilization of this product, we wanted to remind our customers that it's important to not allow this to occur."

Although storing hand sanitizer in your car is convenient while running errands right now, consider storing it in a cool, dry place this summer to err on the side of caution.

If you think you’re showing symptoms of coronavirus, which include fever, shortness of breath, and cough, call your doctor before going to get tested. If you’re anxious about the virus’s spread in your community, visit the CDC for up-to-date information and resources, or seek out mental health support. You can find all of Romper’s parents + coronavirus coverage here, and Bustle’s constantly updated, general “what to know about coronavirus” here.