Hand sanitizers are flammable, with 60-70% alcohol related products. Firefighters have warned that heating up the containers could produce a vapor that can ignite.
The Western Lakes Fire District warned Facebook users of the dangers.
In 2010, however, a flammability test performed by the FAA found the following:
As expected, the hand sanitizer, which is approximately 60% alcohol by volume, is flammable and can easily be ignited with a common grill lighter when poured into a pan. It tends to burn relatively coolly, with peak flame temperatures between 500° and 1000°F, compared to fuel, plastic, or cellulose fires. The observed temperatures above the flame were higher for the liquid hand sanitizer compared to the gel hand sanitizer. The vapor, which is generated by heating the liquid from the bottom, is flammable. The hot liquid does not have to be present to ignite the vapor; however, the vapor could not be ignited at room or elevated ambient temperatures (up to 100°F) without bottom-heating the hand sanitizer.
Cars during the summer can get to temperatures in the 160-170’s F. However the temperatures used to ignite the sanitizer were much higher.
Some sources say the idea of summer heat causing a bottle of hand sanitizer may be a hoax, however. Poynter writes:
This hoax first appeared in Thailand, but eventually spread to Costa Rica and Brazil. Its first incarnation features a video of two young men getting into a car that quickly catches fire burning them alive.
AFP Thailand’s fact-check used a reverse-image search and found the video was actually from 2015. The two young men were Saudis who unadvisedly combined a lighter with an aerosol spray in a confined space. AFP also found an Egyptian news article about the incident.
Costa Rican fact-checking network La Nación discovered that while car fires are not infrequent in Costa Rica, there have been no reports of hand sanitizer causing them.
Brazilian fact-checkers Aos Fatos and Estadão Verifica found that a car would need to reach an internal temperature above 300 degrees Celsius (572 degrees Fahrenheit) to cause hand sanitizer to combust. A study by Arizona State University looking at cars parked in triple-digit summer heat found temperatures topped out around 160 F (71.11 C).
Personally I’ve lived in the desert heat for most of my life and summer car bakes have ruined makeup, crayons, water bottles and aspirin…..so my vote……keep the sanitizer with you.
Daliah Wachs, MD, FAAFP